This small low current inverter operates at 20 kHz frequency. We found it in documentation from the 1980s. The integrated circuit is from that time.
This receiver with two common JFETs was found in an old English documentation. The phone is...
This TTL circuit with the 7493 makes the binary count of the pulses sent by a flip-flop with the...
This circuit was found in a Popular Electronics from the 90s. The counter circuit is not common...