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related_results_labels_thumbs({"version":"1.0","encoding":"UTF-8","feed":{"xmlns":"http://www.w3.org/2005/Atom","xmlns$openSearch":"http://a9.com/-/spec/opensearchrss/1.0/","xmlns$blogger":"http://schemas.google.com/blogger/2008","xmlns$georss":"http://www.georss.org/georss","xmlns$gd":"http://schemas.google.com/g/2005","xmlns$thr":"http://purl.org/syndication/thread/1.0","id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637"},"updated":{"$t":"2025-11-14T00:29:03.296-08:00"},"category":[{"term":"Power Supply"},{"term":"Switches"},{"term":"Amplifier"},{"term":"Audio"},{"term":"Alarm Security"},{"term":"Converter"},{"term":"Bettery Charger"},{"term":"Power Circuits"},{"term":"Regulator"},{"term":"RF"},{"term":"Game Circuits"},{"term":"555"},{"term":"Inverter"},{"term":"Buffer Circuit"},{"term":"Projects"},{"term":"Battery Charger"},{"term":"Apmlifier"},{"term":"LED"},{"term":"Mobil Circuits"},{"term":"Detector"},{"term":"Meters"},{"term":"Sensor"},{"term":"Smartphone"},{"term":"Controllers"},{"term":"Mosfet Circuits"},{"term":"Samsung"},{"term":"Sequencer"},{"term":"Triac Circuits"},{"term":"Doorbell Circuits"},{"term":"IC"},{"term":"Indicator"},{"term":"Microsoft"},{"term":"Solar"},{"term":"Boosters"},{"term":"Computer related"},{"term":"Tube Amplifier"},{"term":"HTC"},{"term":"Nokia"},{"term":"Relay"},{"term":"TV Circuits"},{"term":"Telephone and Intercoms"},{"term":"Transistor"},{"term":"Wireless circuits"},{"term":"iPhone"},{"term":"Android"},{"term":"Apple"},{"term":"Demodulator"},{"term":"Drone"},{"term":"LDR"},{"term":"LG"},{"term":"Motorola"},{"term":"Nexus"},{"term":"PC"},{"term":"Review"},{"term":"Sony"},{"term":"Toy Circuits"},{"term":"Tracking Circuits"},{"term":"Vivo"}],"title":{"type":"text","$t":"Electronic Circuit Diagrams \u0026amp; Schematics"},"subtitle":{"type":"html","$t":"Totally Free Electronic Circuits, Diagrams,Schematics and Projects. We make free Electronic work for student and engineers,."},"link":[{"rel":"http://schemas.google.com/g/2005#feed","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/posts\/default"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/-\/Power+Supply?alt=json-in-script\u0026max-results=6"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/search\/label\/Power%20Supply"},{"rel":"hub","href":"http://pubsubhubbub.appspot.com/"},{"rel":"next","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/-\/Power+Supply\/-\/Power+Supply?alt=json-in-script\u0026start-index=7\u0026max-results=6"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"generator":{"version":"7.00","uri":"http://www.blogger.com","$t":"Blogger"},"openSearch$totalResults":{"$t":"124"},"openSearch$startIndex":{"$t":"1"},"openSearch$itemsPerPage":{"$t":"6"},"entry":[{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-4437145834730884408"},"published":{"$t":"2017-06-24T23:54:00.000-07:00"},"updated":{"$t":"2017-06-24T23:54:59.720-07:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"}],"title":{"type":"text","$t":"0-30 Volt Power Supply"},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nlinear power supply, shown in the schematic, provides 0-30 volts, at one amp, maximum, using a discrete transistor regulator with op amp feedback to control the output voltage. The supply was constructed in 1975-6 \u0026amp; has a constant current mode that is used to recharge batteries.\u003Cbr \/\u003E\n\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgtORVFpCgU2N1R3RxBThOoPTQPDRySeA6K8hMQD0ur45h5cce3ycqeg8cQPj-33loazk2Mde4YA3XdL9LFw743Kb2S-DSkAALnLf-lNLXzQeoaebH_n0iSU4OvDkpTDbt9-1Oz-vOZEU71\/s1600\/power2a.jpg\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgtORVFpCgU2N1R3RxBThOoPTQPDRySeA6K8hMQD0ur45h5cce3ycqeg8cQPj-33loazk2Mde4YA3XdL9LFw743Kb2S-DSkAALnLf-lNLXzQeoaebH_n0iSU4OvDkpTDbt9-1Oz-vOZEU71\/s1600\/power2a.jpg\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEi37_D74Q9nVtyTyqe9j2J57I__48OSPTFN32VmtvfwCoxEFPvPPlVfj-Yh5J3-e3uqYgU8kcpqWSqoJ2MCxH1BlVCkCxlnhEoUlnfeNVeXzVIE2HJyxOsvVyjrivRXz6APZ1934aTNPqBK\/s1600\/power2b.jpg\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEi37_D74Q9nVtyTyqe9j2J57I__48OSPTFN32VmtvfwCoxEFPvPPlVfj-Yh5J3-e3uqYgU8kcpqWSqoJ2MCxH1BlVCkCxlnhEoUlnfeNVeXzVIE2HJyxOsvVyjrivRXz6APZ1934aTNPqBK\/s1600\/power2b.jpg\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cspan style=\"font-size: small;\"\u003EWith reference to the schematic, lamp, LP2, is a power on indicator. The other lamp (lower) lights when the unit reaches its preset current limit. R5, C2, \u0026amp; Q10 (TO-3 case) operate as a capacitor multiplier. The 36 volt zen-er across C2 limits the maximum supply voltage to the op amps supply pins. D5, C4, C5, R15, \u0026amp; R16 provide a tiny amount of negative supply for the op amps so that the op amps can operate down to zero volts at the output pins (pins 6). A more modern design might eliminate these four parts \u0026amp; use a CMOS rail-to-rail op-amp. Current limit is set by R3, D1, R4, R6, Q12, R10, \u0026amp; R13 providing a bias to U2 that partially turns off transistors Q9 \u0026amp; Q11 when the current limit is reached. R4 is a front panel potentiometer that sets the current limit, R22 is a front panel potentiometer that sets the output voltage (0-30 volts), \u0026amp; R11 is an internal trim-pot for calibration. The meter is a one milliamp meter with an internal resistance of 40 ohms. Switch S1 determines whether the meter reads 0-30 volts, or 0-1 amp.\u0026nbsp;\u003C\/span\u003E\u003Cbr \/\u003E\n\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEi5yioNBl__05ItHBMlXyEaVxzEwTy-wIn4Sz7KYgNMLS7uIJfLH5eClv2CBvseQML-NYgPM-CUf0B9T9j6z-JGZMTQV5KVIeutG_PANmRLQNdus5IiuyKJPd-__RNduqxtloqD_U-ofTQX\/s1600\/power2.jpg\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"305\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEi5yioNBl__05ItHBMlXyEaVxzEwTy-wIn4Sz7KYgNMLS7uIJfLH5eClv2CBvseQML-NYgPM-CUf0B9T9j6z-JGZMTQV5KVIeutG_PANmRLQNdus5IiuyKJPd-__RNduqxtloqD_U-ofTQX\/s400\/power2.jpg\" width=\"400\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nA more new circuit might use a single IC regulator, such as the MC78XX, or MC79XX series, immediately after the half wave rectifier, to replace about 30 parts, or at least a high precision zen-er diode to replace D10 as the voltage reference. The LM4040 is such voltage reference \u0026amp; has excellent stability over temperature. IC regulators such as the MC78XX series may finally become obsolete as newer IC regulators are designed, however, discrete transistors, op-amps, \u0026amp; zeners are more generic, have an extended production lifespan, \u0026amp; permit the designer to demonstrate that they understands the principles of linear regulated power supply operation.\u003C\/div\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/4437145834730884408\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/0-30-volt-power-supply.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/4437145834730884408"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/4437145834730884408"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/0-30-volt-power-supply.html","title":"0-30 Volt Power Supply"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgtORVFpCgU2N1R3RxBThOoPTQPDRySeA6K8hMQD0ur45h5cce3ycqeg8cQPj-33loazk2Mde4YA3XdL9LFw743Kb2S-DSkAALnLf-lNLXzQeoaebH_n0iSU4OvDkpTDbt9-1Oz-vOZEU71\/s72-c\/power2a.jpg","height":"72","width":"72"},"thr$total":{"$t":"0"}},{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-6796375314191860402"},"published":{"$t":"2017-06-24T23:35:00.000-07:00"},"updated":{"$t":"2017-06-24T23:35:47.111-07:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"},{"scheme":"http://www.blogger.com/atom/ns#","term":"Projects"}],"title":{"type":"text","$t":"Constructing your own Dual Power Supply "},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nMany times the hobbyist desires to have a simple, dual power supply for a project. Existing power supplies may be large either in power output or physical size. a simple Dual Power Supply is necessary.For most non-critical applications the best \u0026amp; simplest choice for a voltage regulator is the 3-terminal type.The three terminals are input, ground \u0026amp; output.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe 78xx \u0026amp; 79xx series can provide up to 1A load current \u0026amp; it have on chip circuitry to prevent damage in the event of over heating or excessive current. That is, the chip basically shuts down than blowing out. These regulators are cheap, simple to make use of, \u0026amp; they make it practical to design a method with plenty of P C Bs in which an unregulated supply is brought in \u0026amp; regulation is done locally on each circuit board.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThis Dual Power Supply project provides a dual power supply. With the appropriate choice of transformer \u0026amp; 3-terminal voltage regulator pairs you can basically build a tiny power supply delivering up to amp at +\/- 5V, +\/- 9V, +\/- 12V, +\/-15V or +\/-18V. You require to provide the middle tapped transformer and the 3-terminal pair of regulators you require:7805 \u0026amp; 7905, 7809 \u0026amp; 7909, 7812 \u0026amp; 7912, 7815 \u0026amp; 7915or 7818 \u0026amp; 7918.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe user must pick the pair they needs for his particular application.\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cb\u003ENote\u003C\/b\u003E that the + \u0026amp; - regulators do not must be matched: you can for example, use a +5v \u0026amp; -9V pair. However,the positive regulator must be a 78xx regulator, \u0026amp; the negative a 79xx. They have built in plenty of safety in to this project so it ought to give plenty of years of continuous service.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003ETransformer\u003C\/b\u003E\u003Cbr \/\u003E\nThis Dual Power Supply design makes use of a full wave bridge rectifier coupled with a centre-tapped transformer. A transformer with a power output rated at at least 7VA ought to be used. The 7VA rating means that the maximum current which can be delivered without overheating will be around 390mA for the 9V+9V tap; 290mA for the 12V+12V and 230mA for the 15V+15V. If the transformer is rated by output RMS-current then the worth ought to be divided by one.2 to get the current which can be supplied. For example, in this case a 1A RMS can deliver 1\/(one.2) or 830mA.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003ERectifier\u003C\/b\u003E \u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThey use an epoxy-packaged four amp bridge rectifier with at least a peak reverse voltage of 200V. (Note the part numbers of bridge rectifiers are not standardised so the number are different from different manufacturers.) For safety the diode voltage rating ought to be at least to times that of the transformers secondary voltage. The current rating of the diodes ought to be two times the maximum load current that will be drawn.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003EFilter Capacitor\u003C\/b\u003E\u003Cbr \/\u003E\nThe purpose of the filter capacitor is to smooth out the ripple in the rectified AC voltage. There's dual amount of ripple is determined by the worth of the filer capacitor: the larger the worth the smaller the ripple.The two,200uF is an appropriate value for all the voltages generated using this project. The other consideration in choosing the correct capacitor is its voltage rating. The working voltage of the capacitor has to be greater than the peak output voltage of the rectifier. For an 18V supply the peak output voltage is one.4 x 18V, or 25V. So they have selected a 35V rated capacitor.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003ERegulators\u003C\/b\u003E \u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe unregulated input voltage must always be higher than the regulators output voltage by at least 3V in order for it to work. If the input\/output voltage difference is greater than 3V then the excess potential must be dissipated as heat. Without a heat sink three terminal regulators can dissipate about two watts. A simple calculation of the voltage differential times the current drawn will give the watts to be dissipated. Over two watts a heat sink must be provided. If not then the regulator will automatically turn off if the internal temperature reaches 150oC. For safety it is always best to make use of a small heat sink even in case you do not think you will need.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003EStability\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nC4 \u0026amp; C5 improve the regulators ability to react to sudden changes in load current \u0026amp; to prevent uncontrolled oscillations.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003EDecoupling\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe mono block capacitor C2 \u0026amp; C6 across the output provides high frequency decoupling which keep the impedance low at high frequencies.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003ELED\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nTwo LED's are provided to show when the output regulated power is online. You do not must make use of the LED's in the event you do not require to. However, the LED on the negative side of the circuit does provide a maximum load to the 79xx regulator which they found necessary in the coursework of testing. The negative 3-pin regulators did not like a zero load situation. They have provided a 470R\/0.5W resistors as the current limiting resistors for the LED's.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003EDiode Protection\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThese protect chiefly against any back emf which may come back in to the power supply when it supplies power to inductive lots. They also provide additional short circuit protection in the case that the positive output is connected by accident to the negative output. If this happened the usual current limiting shutdown in each regulator may not work as intended. The diodes will short circuit in this case \u0026amp; protect the two regulators.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: center;\"\u003E\n\u003Cb\u003EDual Power Supply Schematic Diagram\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgJ-omevvgOadZRoYMA6N0v3bEh2LY0uJeI6e2MOCh0Gbagw1bKNY5q1B-tEl-cwJI2ZXBgAXyUPNQx0F6WPzoTpNigQ49vtALJNqLz44rfIBoqYLFarTimRQp597Kr-Lq4va-XlQyf_Fgl\/s1600\/Dual+Power+Supply+Schematic+Diagram.gif\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg alt=\"Dual Power Supply Schematic Diagram\" border=\"0\" height=\"201\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgJ-omevvgOadZRoYMA6N0v3bEh2LY0uJeI6e2MOCh0Gbagw1bKNY5q1B-tEl-cwJI2ZXBgAXyUPNQx0F6WPzoTpNigQ49vtALJNqLz44rfIBoqYLFarTimRQp597Kr-Lq4va-XlQyf_Fgl\/s400\/Dual+Power+Supply+Schematic+Diagram.gif\" title=\"Dual Power Supply Schematic Diagram\" width=\"400\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjQ85ZKvIl2EEb3qq5kuqjfNlu72gucv5nR6vk2C2Jf_KUnK1jtmidhyphenhyphenx3Vnu8C8yGy_rYRBeaJ4Y-DtIFf3adGRTRhRzAKxrlomrWk60fWVgpP8dexhIZX_hUDJE5kAI-GuKC_j2qRULv4\/s1600\/Dual+Power+Supply+Schematic+Diagram+1.gif\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"257\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjQ85ZKvIl2EEb3qq5kuqjfNlu72gucv5nR6vk2C2Jf_KUnK1jtmidhyphenhyphenx3Vnu8C8yGy_rYRBeaJ4Y-DtIFf3adGRTRhRzAKxrlomrWk60fWVgpP8dexhIZX_hUDJE5kAI-GuKC_j2qRULv4\/s320\/Dual+Power+Supply+Schematic+Diagram+1.gif\" width=\"320\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/6796375314191860402\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/constructing-your-own-dual-power-supply.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/6796375314191860402"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/6796375314191860402"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/constructing-your-own-dual-power-supply.html","title":"Constructing your own Dual Power Supply "}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEgJ-omevvgOadZRoYMA6N0v3bEh2LY0uJeI6e2MOCh0Gbagw1bKNY5q1B-tEl-cwJI2ZXBgAXyUPNQx0F6WPzoTpNigQ49vtALJNqLz44rfIBoqYLFarTimRQp597Kr-Lq4va-XlQyf_Fgl\/s72-c\/Dual+Power+Supply+Schematic+Diagram.gif","height":"72","width":"72"},"thr$total":{"$t":"0"}},{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-7420898343710213851"},"published":{"$t":"2017-06-19T11:18:00.002-07:00"},"updated":{"$t":"2017-06-19T11:18:21.913-07:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"},{"scheme":"http://www.blogger.com/atom/ns#","term":"Projects"}],"title":{"type":"text","$t":"Constructing a Universal Power Supply using LM317"},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThis is a basic,\u0026nbsp; Universal Power Supply voltage regulator circuit using an LM317, 3-terminal regulator in a TO-220package. The Universal Power Supply output voltage can be set to anywhere in the range one.5V to 30V by selecting resistances. By using a potentiometer, R2, as of the resistors you can dial up the output voltage wanted. Either AC or DC input can be supplied to the PCB by a socket or terminal block. Connection can be either way around. This is because they have provided a bridge rectifier on board. The input DC voltage to the regulator must be at least two.5V above the necessary output voltage. An off\/on switch is provided.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nFor lots of applications (say 12V at 60mA) a heat sink won't be required. The LM317 will provide slightly higher output voltages than 30 volts. However, for most hobbyists over 30V won't be needed. So to make a small PCB they have used some electrolytic capacitors rated to 35 volts. To be safe for continuous operation the maximum input DC voltage to the regulator ought to not be over 33V. With a two.5V to three.0V drop across the regulator this will give a regulated output of 30V. You can draw up to one.5A from the LM317. In case you need higher then use an LM338T rated to 5A.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nWhen outside capacitors are used with any IC regulator it is lovely practice to add protection diodes to prevent the capacitors discharging back in to the regulator in the event of abnormal operating conditions, like a sudden short circuit on the input or the output, or a back emf from an inductive load. That is the function of D one and D Two.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe worth of R1 can range anywhere from 120R to 1200R However, circuits from most other sources settle on using either 220R or 250R. They have used 240R or 250R. The voltage drop across R1is one.25V for all values, and this is the key to the design. one.25V is the reference voltage of the regulator. Whatever current flows through R1 also flows through R2, and the sum of the voltage drops across R1 and R2 is the output voltage. (Additional current Id also flows in R2 but it is usually 50uA so is negligible.)\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe design formula are:\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nVOUT = 1.25 (1 + R2\/R1) volts, or alternatively\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nR2\/R1 = (VOUT\/1.25) - 1\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nSo in case you know VOUT \u0026amp; R1 is 250R then you can calculate R2. In case you find that the 5K potentiometer used forR2 does not give you the degree of fine control over the voltage output range that you need then you can use these formula to fine-tune R1 \u0026amp; R2 to better suited values. \u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEhoqIthnHSWCG5gI5MbZ2ipH-KnzQ7awA4HHe6q_5zBZhqt47fCzHAsrr5UmZ4OB81dW4fZLDksWwv1CBl3rUnr15lmZNnU2vYPXNWJCmTNkT2DAlJaAdpKgl5ShId0gJhw0HdgYCwE-btH\/s1600\/Universal+Power+Supply.jpg\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"247\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEhoqIthnHSWCG5gI5MbZ2ipH-KnzQ7awA4HHe6q_5zBZhqt47fCzHAsrr5UmZ4OB81dW4fZLDksWwv1CBl3rUnr15lmZNnU2vYPXNWJCmTNkT2DAlJaAdpKgl5ShId0gJhw0HdgYCwE-btH\/s320\/Universal+Power+Supply.jpg\" width=\"320\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"http:\/\/risecircuits.blogspot.com\/\"\u003E\u003Cbr \/\u003E\n\u003C\/a\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: center;\"\u003E\n\u003Cb\u003EUniversal Power Supply Schematic Diagram\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"http:\/\/risecircuits.blogspot.com\/\"\u003E\u003Cimg border=\"0\" src=\"https:\/\/www.electronics-project-design.com\/images\/LM317Parts.GIF\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cdiv style=\"text-align: right;\"\u003E\nSourced By : \u003Ca href=\"http:\/\/streampowers.blogspot.com\/\"\u003EStreampowers.blogspot.com\u003C\/a\u003E\u003C\/div\u003E\n\u003C\/div\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/7420898343710213851\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2017\/06\/constructing-universal-power-supply.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/7420898343710213851"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/7420898343710213851"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2017\/06\/constructing-universal-power-supply.html","title":"Constructing a Universal Power Supply using LM317"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEhoqIthnHSWCG5gI5MbZ2ipH-KnzQ7awA4HHe6q_5zBZhqt47fCzHAsrr5UmZ4OB81dW4fZLDksWwv1CBl3rUnr15lmZNnU2vYPXNWJCmTNkT2DAlJaAdpKgl5ShId0gJhw0HdgYCwE-btH\/s72-c\/Universal+Power+Supply.jpg","height":"72","width":"72"},"thr$total":{"$t":"0"}},{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-2098438680847686687"},"published":{"$t":"2017-06-19T11:16:00.000-07:00"},"updated":{"$t":"2017-06-19T11:16:39.557-07:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"},{"scheme":"http://www.blogger.com/atom/ns#","term":"Projects"}],"title":{"type":"text","$t":"12V DC Switch Mode Power Supply Circuit Diagram"},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nIn recent years, the use of switch mode power supply (SMPS) has become more comon as more applications demand for greater power eficiency. It makes use of semiconductor (mostly MOSFET) fast switches to switch DC input that has been rectified at high frequency. The advantages of high frequency switching are that it reduces the size of inductor, capacitors \u0026amp; transformer used. Other advantages of switching power supply over linear power supply are : \u003Cb\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n1) High Efficiency (up to 90% and above for nice design).\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n2) Output can be higher than input.\u003Cbr \/\u003E\n3) Able to operate over a variety of input power supply.\u003Cbr \/\u003E\n4) Able to have over output.\u003Cb\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe setback of using SMPS compared to linear power supply is that it generates electrical noise which contributes to electromagnetic compatibility design issues \u0026amp; more part count.\u003Cb\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003EBuck Converter SMPS\u003C\/b\u003E \u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe SMPS circuit below from Power Integration makes use of LNK304 as its high frequency switch. Take note that this circuit is non isolated type which means that the output is not electrically isolated from the input \u0026amp; all testing ought to be completed using an isolation transformer to provide the AC line input to the board.\u003Cb\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nMake positive that you have electrical safety knowledge \u0026amp; experience before you embark on doing this project.\u003Cb\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe features of this project is as summarized below.\u003Cbr \/\u003E\n\u003Cbr \/\u003E\nInput : 85-265 VAC\u003Cbr \/\u003E\nOutput : 12 V, 120 mA, 1.44 Watt\u003Cbr \/\u003E\nLow Cost : Only 16 components are needed\u003Cbr \/\u003E\nNo-load power consumption : \u0026lt; 0.2 Watt\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjj2snorxYFv9IIjglyYfiYuWMLTCyEHys1BUPQ1L7j_INEDsiim7_YX-5SYUMZEQCQRuUAqYdLejrPodQT9bAtWS1B7PIusDXnzOjwzAlSnOtaKqs59dNspACLNPd8p6XJRnl9Zaa1IS_A\/s1600\/12V+DC+Switch+Mode+Power+Supply.png\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg alt=\"12V DC Switch Mode Power Supply (Rise) \" border=\"0\" height=\"400\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjj2snorxYFv9IIjglyYfiYuWMLTCyEHys1BUPQ1L7j_INEDsiim7_YX-5SYUMZEQCQRuUAqYdLejrPodQT9bAtWS1B7PIusDXnzOjwzAlSnOtaKqs59dNspACLNPd8p6XJRnl9Zaa1IS_A\/s400\/12V+DC+Switch+Mode+Power+Supply.png\" title=\"12V DC Switch Mode Power Supply (Rise) \" width=\"396\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjAUuk9gk_g75wyVFvcIpkHHxgsD8O6b1tHMaXxDpGCsXOImUGeblQjYX7xxOAYvxLaIHVbqs10njGbSFl8GgU8ezTWvUhmHi3MD7cfCi8cuyrdnGGim_XWX2nw6BLYs_AhYZSJGPc7VE0Q\/s1600\/12V+DC+Switch+Mode+Power+Supply+pcb.png\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"400\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjAUuk9gk_g75wyVFvcIpkHHxgsD8O6b1tHMaXxDpGCsXOImUGeblQjYX7xxOAYvxLaIHVbqs10njGbSFl8GgU8ezTWvUhmHi3MD7cfCi8cuyrdnGGim_XWX2nw6BLYs_AhYZSJGPc7VE0Q\/s400\/12V+DC+Switch+Mode+Power+Supply+pcb.png\" width=\"288\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\n\u003Cdiv style=\"text-align: right;\"\u003E\n\u003Cb\u003ESourced By: Circuitsproject.blogspot.com\u003C\/b\u003E\u003C\/div\u003E\n\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/2098438680847686687\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/12v-dc-switch-mode-power-supply-rise.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/2098438680847686687"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/2098438680847686687"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/12v-dc-switch-mode-power-supply-rise.html","title":"12V DC Switch Mode Power Supply Circuit Diagram"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjj2snorxYFv9IIjglyYfiYuWMLTCyEHys1BUPQ1L7j_INEDsiim7_YX-5SYUMZEQCQRuUAqYdLejrPodQT9bAtWS1B7PIusDXnzOjwzAlSnOtaKqs59dNspACLNPd8p6XJRnl9Zaa1IS_A\/s72-c\/12V+DC+Switch+Mode+Power+Supply.png","height":"72","width":"72"},"thr$total":{"$t":"0"}},{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-3769643949175317351"},"published":{"$t":"2017-06-03T03:55:00.000-07:00"},"updated":{"$t":"2017-06-03T03:55:04.584-07:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"},{"scheme":"http://www.blogger.com/atom/ns#","term":"Projects"}],"title":{"type":"text","$t":"Variable DC Power Supply Circuits Diagram"},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThis project provides the schematic \u0026amp; the parts list needed to construct a simple DC Power Supply from an input power supply of 7-20 V AC or 7-30V DC. This project will come in handy in case you use plenty of batteries for your basic electronics project.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nTwo DC voltage outputs are available; is a fixed regulated 5V for TTL use. The other output is variable from 5V upwards. The maximum output voltage depends on the input voltage. The specified maximum input DC voltage to the regulator is 35V. The maximum input voltage must be two volts higher than the regulated output voltage.\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cb\u003EVariable DC Power Supply Circuits Diagram \u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjla3zTEG3Qbv4n5ZYTwvSv0zAcydN6lcYFWR76F-XvNHkBhRJvvWJhIUSzx_JYv1YUgxjeB2YS80xT-CZM0LtBBCX5qBavAvJib37kzCmihRt0qNhB3TNectLqH8twq6PMTVwLTDObOWQS\/s1600\/Variable+DC+Power+Supply.GIF\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg alt=\"Variable DC Power Supply Circuits Diagram\" border=\"0\" height=\"205\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjla3zTEG3Qbv4n5ZYTwvSv0zAcydN6lcYFWR76F-XvNHkBhRJvvWJhIUSzx_JYv1YUgxjeB2YS80xT-CZM0LtBBCX5qBavAvJib37kzCmihRt0qNhB3TNectLqH8twq6PMTVwLTDObOWQS\/s400\/Variable+DC+Power+Supply.GIF\" title=\"Variable DC Power Supply Circuits Diagram\" width=\"400\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe DC Power Supply circuit is based around the 7805 voltage regulator. It's only three connections input, output \u0026amp; ground \u0026amp; it provides a fixed output. The last digits of the part number specify the output voltage, e g. 05, 06, 08, ten, 12,15, 18, or 24. The 7800 series provides up to one amp load current \u0026amp; has on-chip circuitry to close down the regulator if any attempt is made to operate it outside its safe operating area.It can be seen that there's in fact separate circuits in this power supply. 7805 is directly connected as a fixed 5V regulator. The second 7805 has a resistor divider network on the output. A variable 500 ohm potentiometer is used to vary the output voltage from a maximum of 5V up to the maximum DC voltage depending on the input voltage. It will be about 2V below the input DC voltage.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe capacitor across the output improves transient response. The giant capacitor across the input is a filter capacitor to help smooth out ripple in the rectified AC voltage. The larger the filter capacitor the lower the ripple.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nFor tiny applications the heat sinks won't be needed. The tab on the regulator will dissipate 2W at 25 o C in air. (This is equivalent, for example, to an input voltage of 9V, an output of 5V \u0026amp; drawing 500 m A.) However, as your projects get bigger they will draw more current from the power supply and the regulators will operate at a higher temperature and a heat sink will be needed. You can basically add voltage \u0026amp; current meters to it and put it in to an appropriate plastic case connected to a transformer.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003C\/div\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003E\u003Cbr \/\u003E\u003C\/b\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cb\u003ETrouble Shooting Procedure\u003C\/b\u003E\u003Cbr \/\u003E\n\u003Cbr \/\u003E\nAn LED has been put in to the output of the fixed 5V regulator to indicate that the circuit is working. Poor soldering is the most likely reason that the circuit does not work. Check that all the soldering is done properly. Check that all parts are in their correct position on the PCB. Other items to check are to make sure that the regulators, electrolytic capacitor \u0026amp; bridge rectifier are inserted in the correct orientation.\u003C\/div\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/3769643949175317351\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/variable-dc-power-supply-rise.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/3769643949175317351"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/3769643949175317351"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/variable-dc-power-supply-rise.html","title":"Variable DC Power Supply Circuits Diagram"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjla3zTEG3Qbv4n5ZYTwvSv0zAcydN6lcYFWR76F-XvNHkBhRJvvWJhIUSzx_JYv1YUgxjeB2YS80xT-CZM0LtBBCX5qBavAvJib37kzCmihRt0qNhB3TNectLqH8twq6PMTVwLTDObOWQS\/s72-c\/Variable+DC+Power+Supply.GIF","height":"72","width":"72"},"thr$total":{"$t":"0"}},{"id":{"$t":"tag:blogger.com,1999:blog-6970617591501949637.post-5708645057526402403"},"published":{"$t":"2017-01-28T03:56:00.000-08:00"},"updated":{"$t":"2017-01-28T03:56:49.826-08:00"},"category":[{"scheme":"http://www.blogger.com/atom/ns#","term":"Power Supply"},{"scheme":"http://www.blogger.com/atom/ns#","term":"Projects"}],"title":{"type":"text","$t":"Variable 5 to 20V DC Supply"},"content":{"type":"html","$t":"\u003Cdiv dir=\"ltr\" style=\"text-align: left;\" trbidi=\"on\"\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nIf you are looking for a low drop voltage regulator that can provide a power supply of 1A with an output voltage of between 5V and 20V DC, National Semiconductor LM2941 Low Dropout Adjustable Regulator is that you can pick to make use of. It's a typical dropout voltage of 0.5V which means that the input supply need only must be 0.5V DC over the desired output voltage. Its other features include internal short circuit current limit and reverse battery protection.\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nAs shown in the schematic below, the regulator has five pins which consists of the ON\/OFF control, Input Voltage, Output Voltage, Ground \u0026amp; Adjustable pins. ON\/OFF is used for the purpose of switching on \u0026amp; off of the regulator. The capacitors C1 \u0026amp; E1 are to be placed as close as feasible to the regulator.\u003Cbr \/\u003E\n\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjKaLt1eMlXxrQ4MdolPXKIcBi4MEZHTgOP8rertogbdQQYWBgvHhw6nVnmLPpbJ4IL-uEKCWuJWeEkJHNiruRTzwNPDcF2NeZyXPdGCemz4ME_2y-stJLNuuv6iRFMZN2Zdwck8DjxX0z3\/s1600\/Variable+5+to+20V+DC+Supply.gif\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"292\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjKaLt1eMlXxrQ4MdolPXKIcBi4MEZHTgOP8rertogbdQQYWBgvHhw6nVnmLPpbJ4IL-uEKCWuJWeEkJHNiruRTzwNPDcF2NeZyXPdGCemz4ME_2y-stJLNuuv6iRFMZN2Zdwck8DjxX0z3\/s400\/Variable+5+to+20V+DC+Supply.gif\" width=\"400\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\nThe output of the circuit can be varied by varying the worth of potentiometer VR1 from 5V DC to 20V DC. The input voltage is limited from five.5V DC to 30V DC. Resistor R1 must be greater than 1K. The worth of the VR1 that needs to be set is calculated from the formula given below:\u003C\/div\u003E\n\u003Cdiv style=\"text-align: justify;\"\u003E\n\u003Cbr \/\u003E\u003C\/div\u003E\nVR1 = R1[(Vout\/1.275) - 1] ohm\u003Cbr \/\u003E\n\u003Cbr \/\u003E\nIf R1=1K, Vout = 5V, VR1 should be set to 2.9K ohm.\u003Cbr \/\u003E\n\u003Cbr \/\u003E\nIf R1=1K, Vout = 20V, VR1 should be set to 14.7K ohm\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cdiv class=\"separator\" style=\"clear: both; text-align: center;\"\u003E\n\u003Ca href=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEiLxFlTG2MEz1yhqbBm0Ezw-TCTonNIDMzLLffmjDIQYlgxvDzqcc7mrESz36JOcMZYRMqAlhXYCvtNRTJmlJGeGTcamkTHsWUrPaQ6ccRldy6PACZEUeh3nlRnWH4h-jMmD7qEmpDGJAr_\/s1600\/Variable+5+to+20V+DC+Supply+1.gif\" imageanchor=\"1\" style=\"margin-left: 1em; margin-right: 1em;\"\u003E\u003Cimg border=\"0\" height=\"245\" src=\"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEiLxFlTG2MEz1yhqbBm0Ezw-TCTonNIDMzLLffmjDIQYlgxvDzqcc7mrESz36JOcMZYRMqAlhXYCvtNRTJmlJGeGTcamkTHsWUrPaQ6ccRldy6PACZEUeh3nlRnWH4h-jMmD7qEmpDGJAr_\/s400\/Variable+5+to+20V+DC+Supply+1.gif\" width=\"400\" \/\u003E\u003C\/a\u003E\u003C\/div\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003Cbr \/\u003E\n\u003C\/div\u003E\n"},"link":[{"rel":"replies","type":"application/atom+xml","href":"https:\/\/circuitsstream.blogspot.com\/feeds\/5708645057526402403\/comments\/default","title":"Post Comments"},{"rel":"replies","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/variable-5-to-20v-dc-supply-rise.html#comment-form","title":"0 Comments"},{"rel":"edit","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/5708645057526402403"},{"rel":"self","type":"application/atom+xml","href":"https:\/\/www.blogger.com\/feeds\/6970617591501949637\/posts\/default\/5708645057526402403"},{"rel":"alternate","type":"text/html","href":"https:\/\/circuitsstream.blogspot.com\/2011\/07\/variable-5-to-20v-dc-supply-rise.html","title":"Variable 5 to 20V DC Supply"}],"author":[{"name":{"$t":"Funny life"},"uri":{"$t":"http:\/\/www.blogger.com\/profile\/00021003145250222085"},"email":{"$t":"noreply@blogger.com"},"gd$image":{"rel":"http://schemas.google.com/g/2005#thumbnail","width":"16","height":"16","src":"https:\/\/img1.blogblog.com\/img\/b16-rounded.gif"}}],"media$thumbnail":{"xmlns$media":"http://search.yahoo.com/mrss/","url":"https:\/\/blogger.googleusercontent.com\/img\/b\/R29vZ2xl\/AVvXsEjKaLt1eMlXxrQ4MdolPXKIcBi4MEZHTgOP8rertogbdQQYWBgvHhw6nVnmLPpbJ4IL-uEKCWuJWeEkJHNiruRTzwNPDcF2NeZyXPdGCemz4ME_2y-stJLNuuv6iRFMZN2Zdwck8DjxX0z3\/s72-c\/Variable+5+to+20V+DC+Supply.gif","height":"72","width":"72"},"thr$total":{"$t":"0"}}]}});