Crystal Tester (T329E)

This circuit is from a 1964 publication. The circuit tests crystals from 2 to 20 MHz with good accuracy. The power supply is included.

Ultrasonic Oscillator (NI008E)
The 50 kHz signal generated by this circuit is applied to a low impedance inductive transducer. A...
Amplifier with the 4049 (CB4770E)
This different audio amplifier was found in a 90's Electronic Design. The circuit uses components...
Analog-to-Digital Converter – 555 (NI024E)
This circuit converts a resistance in the range between 1 k ohm and 1 MΩ to a signal in a...