Matching antenna (CB7458E)

The coil and sockets of this circuit found in a QST depend on the frequency band that is intended to be tuned.

Four Quadrant Conductive Photo Detector CB4946E (CB4946E)
This circuit was found in an 80's documentation using an NE5514, operating at the time. The font...
Wien Bridge Oscillator (CB8089E)
This circuit generates sinusoidal signals between 300 and 3000 Hz. We find a 303 Circuits from the 90's....
Adjustable DC Protector (CB18113E)
This circuit from a 2003 documentation, has a protection system that disarms the power supply if...