This negative voltage source was found in a Popular Electronics from the 90's. The transformer has 120V secondary and 4-12V primary.
This oscillator generates quadrature signals, that is, with a 90-degree lag. The frequency is...
This interesting sine wave oscillator circuit for the audio track uses an incandescent light bulb...
This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the...