DC voltage measuring instrument circuit schematic

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Shunuo varistor / ESD varistor / product complete / Sunlord first-class agent

Test - lowercase jpg

Kaixin micro test

The 555 terminal 5 and threshold 6 pins are actually the two inputs of the internal voltage comparator I. As long as the 6-pin voltage is higher than the 5-pin 5mV, the 555 will be reliably triggered.
Add DC voltage to the + and - terminals in the figure. If the voltage is high, LED1 is on, the voltage is low, and LED2 is on. Change the range and RP1. When the two LEDs alternately flash, the range is multiplied by the RP1 indicator, which is the measured voltage volts. The measurement range has four steps: 0~1V, O~10V, O~100V, 0~1000V.