Found in Motorola documentation from the 1970s, this circuit makes use of period components. The lamp is used as a stabilizing device. The signal is sinusoidal.
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...