Using an operational amplifier, this circuit from a 90s Popular Electronics, is characterized by its high sensitivity. R5 can be added to control the gain.
This configuration is also valid for other operators and the formula for calculating the gain is...
This low power, class A circuit uses two old germanium transistors. The circuit was found in an...
This circuit is from a 90s 73 Amateur Radio Today. The circuit uses a MOSFET to provide 10 W of...