This circuit was obtained in a 90s Popular Electronics. It is used for tuning on AM radios. The field effect transistors used support equivalents.
The basis of this circuit is a CA3130 operational amplifier. The transistor can be BC548, and the...
Found in a Popular Electronics from the 90s, this circuit uses components that are still current....
This “test your nerves” game was found in old documentation. The SCR can be of any sensitive type,...