Found in 1965 Radio Shack documentation, this circuit has a crystal phone output in the 14.8 kHz range. The coil consists of 200 turns of wire 25 in a 1.5 m side square.
This circuit generates frequencies determined by R3 and C1. We found it in the Radio Electronics magazine...
The configuration below is suggested by the National Semiconductor Linear Applications Handbook. The...
This charger circuit provides an initial voltage of 2.5 V and when the current reaches 180 mA the...