Using a standard multimeter, this circuit from a 73 magazine for radio amateurs provides an output proportional to the inductance under test. The circuit is TTL and must be powered with 5 V.
This circuit can operate with signals from 1.5 to 150 MHz. C1 is 36 pF and C2 is 4n7. The diode...
This circuit was found in a 90s Popular Electronics. It prevents the power from being switched...
Any high-gain Darlington transistor can be used on this touch circuit. The load can be formed by...