This circuit was found in a 90s Popular Electronics. The circuit uses components from that time, intended to receive signals in the range of 150 to 250 kHz.
In this circuit, the relay remains closed by activating a lamp, for a time that depends on the...
The figure shows how to connect a 7400 to obtain a bistable configuration. The circuit must be...
The circuit is from an old documentation making use of an operational amplifier of the time. The...