Found in Motorola's 1967 documentation this circuit can use any general-purpose transistor. The signal should be applied to a good amplifier. The noise diode can be replaced with a common one.
This circuit was found in an American publication from 1968. The transistors are from the time,...
The components of this circuit are exchanged for modern equivalent such as 470 K for the pot and...
This circuits shows how to use in operational amplifier as a basic voltmeter. Power supply must be...