This high impedance headphone amplifier was found in American documentation from the 1990s. Any general-purpose FET can be used.
This simple logic level tester was found in Radio Electronics from the 90s. The inverters are of...
The low-noise amplifier shown uses a rare Raytheon operational amplifier today. The circuit can be...
This circuit, found in American documentation, works as a voltage doubler, enabling the supply of a...