We found this circuit in the May 1990 issue of Radio Electronics magazine. The circuit is powered by the relay used and uses both normally open and normally closed sensors.
This circuit generates noise pulses for audio equipment probes. The circuit is from a 90’s 303...
This modulated light transmitter was found in a 90s Popular Electronics. In place of the lamp with...
This circuit, found in a 1958 magazine, is for reference only, since the components are not easy...