Found in a Popular Electronics from the 90s, this shield is activated by a 20 mA current. The inverter is an Open Collector TTL type. The power is 5 V.
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...