With this circuit it is possible to use a pair of old telephones in a wired communication system. The circuit is from a Popular Electronics from the 90s.
We found this timer circuit in a publication in the 90's to turn off a device powered by 4...
This circuit is suitable for use with 1400 kHz range FI receivers. Changes can be made to other IF...
The transistors of this 12 V x 150 mA power source can be BC558 for PNP and BD135 for NPN. The...