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 of a few tens of milliwatts of power requires a single source. We found it in a Radio...
Found in Popular Electronics this circuit will trigger a buzzer if the ignition key is removed...
May 2017 - The new 36V TLVx171 Series of General Purpose Operational Amplifiers from Texas...