Found in a Popular Electronics from the 90s, this circuit generates signals from 2 Hz to 30 kHz in different bands. The circuit can be powered by voltages from 5 to 12 V, depending on the application.
Using an integrated circuit from the time, this circuit was found in Radio Electronics from the...
This shield circuit is from old documentation. The operational amplifier used is not common today...
This circuit powers a small 5 W lamp that goes out when power is lost. The circuit can use the...