This LED diode test is suggested by the Texas Instruments optoelectronics manual. The transformer current can be between 50 mA and 300 mA and the voltage between 6 and 9 V.
This well-designed sinusoidal oscillator by Wien bridge was found in ancient European...
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...
Found in a Popular Electronics from the 90's, this circuit can be implemented with almost any...