Ultrasonic Remote Control Test (CB21309E)

This circuit was found in a Popular Electronics from the 90s. The circuit uses an ultrasonic microphone. The indicator is dual with LED and Buzzer.

| Clique na imagem para ampliar |

Touch Sensor 4013 (CB15761E)
This circuit fires at the touch of a sensor, passing its output from high to low in a time given by...
Binary Counter using Relays (CB6607E)
This circuit was found in a 1967 US publication. In it we have the implementation of a ring...
Touch Volume Control (CB12470E)
The strength of an audio signal can be controlled by touching sensors. Keeping the finger in...