This circuit is designed to peak charge Rx and Tx batteries. It’s programmed for a C/2 charge rate for 250mAh and 500mAh batteries (charge currents of 125mA or 250mA). It’ll charge Rx from 12V at the field, Tx from a 15V supply (like a car w/engine running). Use a 15-18V supply to charge at home (you should be able to find wall cubes with this rating). It is based on a Maxim IC, the MAX713.
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