A constant current source source can supply a fixed current to a load regardless of input voltage or load change. LM317 / LM350 / LM338 constant current source is one of the simplest design. The LM317 is quite useful as a constant current source, works on a wide input voltage range, from 3V up to 40V. So, here’s the LM317 based constant current source, it’s design and a little about it’s working principle.
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]