This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The tunnel diode is an uncommon component today.
This circuit, found in a Popular Electronics from 1978, causes two LEDs to flash alternately for a...
This 555 timed touch switch was found in a 90s Hands-On Electronics. It triggers a buzzer, but a...
We found the circuit of this Japanese transistorized commercial receiver in a documentation from...