This circuit is from a Radio Electronics magazine from August 1974. It used one of the first photomultiplier tubes that was to be powered by high voltage. The power came from the mains.
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,...