Field strength meter (CB8220E)

This passive tuned circuit was found in a 90s Popular Electronics. The coils must be according to the monitored waveband.

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Battery charge indicator (CB9135E)
Found in 80's Radio Electronics, this circuit uses an LED to indicate that a battery is being...
Bootstrap with capacitor (CB8939E)
We found this circuit in a 1965 General Electric documentation. The circuit generates synchronized...
Simple Power Control with Diodes (CB11971E)
At each switch position, a diode is connected in series with the motor, thus causing a small...