In this project we have a tendency to design a circuit to build an electronic voltmeter while not making use of any microcontroller. Here we have a tendency to employ a very moderate IC for voltage activity, particularly ICL7107/CS7107. Making use of ICL7107, we are able to build a correct and very affordable digital voltage measurement meter. ICL7107 may be a 3.5 digit analog to a digital device (ADC) that consumes extremely low power. The IC has an internal circuit for driving four 7-segment displays to show the measured voltage. It additionally encompasses a clock circuit and a reference voltage supply.
Figure 1: Simple digital voltmeter Circuit
- 7 segment LED display (Quantity: 4)
Circuit Diagram and Working Explanation
The working of this electronic voltmeter circuit is extremely straightforward. ADC within the IC is a desegregation device or twin-kind analog to digital device. Internal ADC of this IC reads the voltage to be measured and compares it with an indoor reference voltage and converts that into the digital equivalent. Then this digital equivalent is decoded for the 7-segment displays by a driver circuit within ICL7107 and so shown over four 7-segment diode displays.
Here electrical device R1 and electrical capacitor C1 area units won’t set the frequency of the internal clock of ICL7107. Electrical capacitor C2 filters the fluctuations in internal reference voltage and provides stable reading on 7-segment displays. R5 is to blame for dominant the variations of the meter. (R5=1K for 0-20V vary and 10K for 0-200V range). RV1 could be a potentiometer which can be used for calibrating the voltage of meter or may set the reference voltage for internal ADC.
This circuit includes four common anode 7-segment displays with a negative voltage indicator. This circuit ought to be operated at 5V voltage offer, that’s why we've got used a 7805 transformer IC to provide 5v to the circuit still as for preventing the injury of ICL7107.
Negative Voltage Supply: Here we have to be compelled to offer negative power to PIN 26 of the ICL7107. The 555IC timer IC is designed here as ASTABLE multi-vibrator. The electrical device here may be modified but the choice ought to pursue for optimum negative voltage. If hand-picked capacitance doesn't suit well, then we have a tendency not to get the most negative voltage at the output. Here we've used 100nF and 10uF.
Figure 3 Block diagram of the circuit implementation
PCB Design using Wellpcb
They recently launched their part sourcing service where they also have available stock of electronic parts and users can order their needed parts beside the PCB.
Figure 4 Top layer PCB layout
Figure 5 Photo view of the voltmeter
Calculating and Ordering Samples Online
After finishing the look of the PCB, you'll be able to click and order it online. You can try the prototype facility provided by the company. Here you'll be able to read your PCB in Gerber Viewer or transfer Gerber files of your PCB. Also you'll be able to choose the quantity of PCBs you would like to order, what percentage copper layers you wish, the PCB thickness, copper weight, etc. You can get an instant quote by using the link below:
Below are the images after the soldering of the components on the PCB: