Adjustable hysteresis (CB21515E)

This circuit was suggested by a 1967 Electronic Design. Modern equivalent transistors can be used.

| Clique na imagem para ampliar |

Crystal unijunction oscillator (CB20679E)
This circuit was obtained in an Electronics World of 1969. It is a crystal oscillator with a 100...
Variable Gain Instrumentation Amplifier (CB15876E)
This circuit, shown in the figure, consists of a variable gain amplifier with differential input...
Precision Shadow Alarm 741 (CB25479E)
This circuit was found in the July 1992 Radio Electronics magazine. Sensitivity adjustment is made...