LM317T Voltage Regulator with Pass Transistor

Link to page: www.pcbheaven.com This is the remake of the third episode of the LED driving and controlling methods Theory Series. In this episode i explain how can someone design a constant current LED driver with a single transistor, biased with a Zener diode to achieve constant current regulation regardless of the power supply voltage. Additionally, i analyze a second circuit with sme functionality but instead of the Zener diode i use two simple diodes. On-line calculator for this circuit: www.pcbheaven.com



http://www.youtube.com/watch?v=fMc99rM6u4k&hl=en

Its just as simple as adding a resonant capacitor across the primary of the flyback (in my case it was about .20uF) and adding an inductor of some kind in series with the + and the primary of the flyback. The next step is a half bridge. But thats after I get my second breadboard. All I need to do now, is get my breadboard, add a 12 volt regulator for the 555 timer, and get a .22uF capacitor *more than 250 volts!!!*



http://www.youtube.com/watch?v=09kbwbQcl8Q&hl=en

Well we had a little set back but still found time for some fun... the tow truck driver wanted to see what all the fuss was about so we showed him. Little Demoing for the guys at the shop and showing the car up on the lift that i got my new rims and tires from... the guys at the shop were nice enough to let me take the wheels evven though they didnt have replacements. he left the car up on the hoist untill they could get some. not to mention this was taken an hour after they closed... Thanks guys DelReal Auto Sales Lafayette Indiana



http://www.youtube.com/watch?v=TC_EbpZ4H-c&hl=en

LED power driver on the basis of LM317 chipLEDs have become very popular lately. They are used to light up pretty much everything.However, LED is quite a fragile component. It can break when affected by voltage drops, continuous operation in peak modes, and incorrect connection. It is important to know that LED's main longevity parameter is not its power supply voltage but the current which flows through it.I'd like to show you a simplest current regulator which is quite reliable at the same time. It can be easily used in various feed circuits of LEDs.The circuit of such regulator is quite simple. To stabilize voltage "ajust" terminal is usually connected to earth, through a resistor or without it. In this case it is connected with a regulator output.So you can see that you need only one resistor to transform LM317 chip into LED power driver!Rated value of the resistor can be calculated with this simple formula. So we'll have 62 Ohms of rated resistance for an LED with a 20mA current. The chip's maximum input voltage equals 37V. That means you should use the regulator for voltage up to 37V.The only condition that you have to follow is that you must select the number of LEDs in such a way so that the regulator has as little voltage left as possible - but no less than 1.3V. This is necessary for reducing dissipated power on the regulator itself. It is especially important for large currents.And do not forget to install a chip onto the radiator at 350 mA currents or above.



http://www.youtube.com/watch?v=AKuLLyl3pCY&hl=en

Hi all. I decided to make this guide because I couldn't seem to find one already made on youtube. I made this guide really simple for a really simple kind of person. There is also a schematic at the end. And then another simpler schematic for beginners. This driver can be used for Red laser diodes and Blu-ray laser diodes. Good luck!



http://www.youtube.com/watch?v=BI7iuBze5I8&hl=en