Using the LM170 integrated circuit, this circuit was found in the May 1970 Radio Electronics magazine. The transistor is general-purpose, and the potentiometer adjusts the gain.
This circuit uses two Raytheon RC4558 operational amplifiers that are similar to the 741. The...
This small stereo amplifier for headphones was found in a documentation on integrated circuits from...
This is a MOSFET version of a grid dip meter for frequencies between 1.8 MHz and 150 MHz,...