This high and low output of IC generates a square wave and causes LEDs to blink. When the voltage at the capacitor becomes higher than inverting input pin it starts to discharge and again the output of IC becomes high. When the charge (voltage) of the capacitor exceeds the voltage at inverting pin (pin 2), the output of IC becomes LOW, as a result, the LED stops glowing. Where the battery is connected to the circuit the voltage at pin 3 is high compared to the voltage at pin 2 due to the charging of the capacitor, as a result, the output of IC becomes high, and the LED starts to glow.Īt this instant capacitor start to charge through the resistor R4. The voltage at pin 3 (noninverting pin) is fixed whereas the voltage at pin 2 (inverting pin) varies due to the charging and discharging of capacitor C1. The IC to be tested is configured in voltage comparator mode. Working of the circuit | Operational Amplifier 741 Tester An LED 1 is used to indicate whether IC is good or fault. All the components are connected as shown in the circuit diagram. The circuit of the operational amplifier 741 tester comprises two diode and very few passive components and a 741 IC to be tested. Circuit Description of Operational Amplifier 741 Tester Now here is a simple circuit operational amplifier 741 tester which test op-amp 741 either is good or fault. Various type of circuit based on op-amp 741 is already posted in on the op-amp section.

741 inverting amplifier pin schedule