Voltage to frequency converter (CB8928E)

Found in ancient American documentation, this circuit uses an operational amplifier of the time, which is uncommon today.

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Square oscillator (CB8450E)
This circuit was found in a 90s Popular Electronics. The frequency is determined by R3 and C1 that...
600W heating control (CB21383E)
Found in old American documentation, this circuit is intended for the control of heating elements. The...
Gain 100 FET Amplifier (CB13309E)
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