This is LiPo battery charger circuit based around the MAX1551 / MAX1555 chip from Maxim ICs. And it happens to be a very easy chip to use. I used the typical circuit from the datasheet and referred to the pin out to see which pin is what. I also used adapter board so that I could prototype the LiPo battery charger on a breadboard. The barrel plug towards the top goes into an LM7805 that can take 7-16V and regulates it down to 5V. Besides that, pretty simply stuff with only a handful of common components.
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]