lm324 quality test

To judge the quality of the four operational amplifiers of LM324, you can connect the four operational amplifiers according to the figure. The two 10K resistors R1 and R2 in the figure form a voltage divider circuit. If Vcc is 6V, it is the reverse of the four operational amplifiers. The phase input terminal provides a DC voltage of approximately 3V.

1. When SA1 switch 1 and 2 are turned on, U1A's 3 pin is connected to +6V power supply, U1A's 1 pin output is high level (about 6V), therefore, U1B-U1D also output high level (+6V ), so that the light-emitting diode LED is turned on and emits light.

2. When SA1 switch 1 and 3 are turned on, U1A's 3 pin is grounded, U1A's 1 pin outputs the bottom level, so U1B-U1D all output the bottom level, and the LED is off.

If the LED does not change with the position of SA during detection, it means that one or more op amps have been damaged.

The pictures are as follows:

LM324 detection method and pin diagram

LM324 is composed of 4 identical operational amplifiers, so 4 pins with the same function have basically the same forward and reverse resistance values to the ground. The detection method and resistance are introduced with the operational amplifiers of pins 8, 9, 11 and The value is the same as other detection methods. Use the multimeter to measure the diode file.

(1) A black test lead connects to 11 pins, red test lead 8 pins, the resistance value is 1997. b. Connect the black test lead to 8-pin red test lead to 11-pin, and the resistance is about 658. c. The black test lead is connected to pin 9 and the red test lead is connected to pin 11. The resistance is not large. d Connect the black test lead to pin 11 and the red test lead to pin 9, and the resistance is about 712. e The black test lead is connected to 10 pins, and the red test lead is connected to 11 pins. The resistance value is about no large. f The black test lead is connected to pin 11, and the red test lead is connected to pin 10. The resistance is about 711.

(2) Detection of the resistance value of the power supply terminal to the ground

The power supply terminal of LM324 is 4 and 11 feet, we only need to measure the resistance of the positive and negative resistance. a. The black test lead is connected to pin 4 and the red test lead is connected to pin 11. The resistance is about 581. b. Connect the black test lead to pin 11 and the red test lead to pin 4. The resistance is about 1.272.