Simple Circuit Diagram With Voltmeter. Ry 2000 range 0 2 k ohms rx 10m. A transistor is a current controlled device so resistance is inserted in series with the transistor q 1 to select the voltage range.
The circuit as it is described here can display any dc voltage in the range of 0 1999 volts. Here is the schematic diagram of the circuit. Talking about the circuit diagram below the unit is a complete fledged digital voltmeter circuit that are available for calculating direct voltages starting from zero to 199 volts.
The resistor r1 and capacitor c1 are used to set the internal oscillator clock frequency at 48hz clock rate at which there will be three readings per second.
Even a fast response meter need this circuit since our visual perception won t be able to catch a fast event. The center point of two resistors r1 and r2 which makes the voltage divider circuit is connected to arduino pin a0. If you want more the voltage range. Adc inside the ic is integrating converter or dual type analog to digital converter.
