I = i*4.89 // Converting ADC value to mVīy using values V and I we can calculate the Input Voltage and Current across the Load (Connected across Output terminals). I = ADC_Read(3) // ADC value of channel 3 (current) So voltage input to the analog pin of PIC can be calculated as follows… v = ADC_Read(2) // ADC value of channel 2 (voltage) Thus it means that for a change in 4.887mV, the binary output changes by 1. We want to convert this digital to corresponding voltage in decimal. The ADC module of PIC converts analog input to 10 bit digital number.

5.1V Zener Diode is added in parallel to these analog input pins to protect PIC from over voltages. 47 ohm resistor is also feedback to the analog pin RA3 via 100K ohm resistor. Voltage and Current Sampling circuit is shown below. When the Input voltage is 30V (max) the voltage across 20K ohm resistor becomes 5V which is feedback to the analog pin RA2 of the PIC Microcontroller. 47 ohm special resistor with fuse (shown in figure) and current is calculated. To minimize the path resistance we will use.

Current through a circuit can be measured by introducing a 1 ohm resistor and measuring the voltage across it. So we will map 0 to 30V to 0 to 5V by using a voltage divider. This circuit is designed to measure 0 to 30V. The analog input to PIC is limited to VSS and VDD voltages (0 – 5V) of PIC. LCD Interfacing with PIC MicrocontrollerĪDC module of PIC Microcontroller converts the Signals on its analog pin to 10 bit binary data and it has software selectable high and low voltage reference input to some combination of VDD, VSS, RA2 and RA3.If you don’t know the basis of PIC ADC and LCD Interfacing please read the following articles. I suggest to use PIC with low pin numbers and multiplexed 7 segment display if you wish to use this as your measuring instrument. PIC16F877A is enough if you do this project only for testing purposes. I am using PIC16F877A and the result is displayed on an LCD Display. Voltmeter and Ammeter can be easily made using PIC Microcontroller having ADC (Analog to Digital Converter).

Volt meter proteus library