This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
In this circuit the capacitor under test is charged at switch position A and then discharged...
This LED light effects circuit is from 1988, but uses common components nowadays. The LEDs are...
This circuit can operate with signals from 1.5 to 150 MHz. C1 is 36 pF and C2 is 4n7. The diode...