Simple LIPO saver board to throw onto lithium based batteries for overvoltage protection. It consists of a TLV3012 comparator with onboard reference, an voltage divider, load resistors, indicator LED and a transistor. It should turn on the transistor, and load LIPO battery cell when its voltage is >4.25V
Ive attached LIPO saver schematic. The diode represents the onboard reference in the comparator, eagle didn't have the device in its library.
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]