Introduction: Simple Digital Voltmeter Circuit With PCB Using ICL7107

About: WELLPCB PTY LTD is a daughter company of Uniwell Circuits Co., Ltd, which have two modern PCB factories, founded in Shenzhen, China in April, 2007. WELLPCB is focusing on online prototy…

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 employing a very moderate IC for voltage activity particularly ICL7107/CS7107. Making use of ICL7107, we are able to build correct and really low price digital voltage measurement meter. ICL7107 may be a 3.5 digit analog to digital device (ADC) that consumes extremely low power. The IC has internal circuit for driving four seven section show to show the measured voltage. It additionally encompasses a clock circuit and a reference voltage supply.

Step 1: Requirements of Components

  • IC7107
  • LM555
  • PCB (
  • LM7805
  • Common anode 7 segment LED display (Quantity: 4)
  • Terminal Block 2 pin (2)
  • 47k
  • 1k (5)
  • 22k
  • 10K
  • 120K
  • Pot 5K
  • 100nF (3)
  • 10uF (2)
  • 100pF
  • 220nF
  • 47nF
  • Power Supply 9v/12v
  • Berg sticks (2)
  • 40 pin IC base
  • 8 pin IC base
  • Probe or wire
  • 1N4148 diode (2)

Step 2: Circuit Diagram and Working Explanation

Working of this electronic voltmeter Circuit is extremely straightforward. ADC within the IC is desegregation device or twin kind Analog to digital device. Internal ADC of this IC reads the voltage that to be measured and compare it with an indoor reference voltage and converts that into the digital equivalent. Then this digital equivalent is decoded for seven section Displays by driver circuit within ICL7107 and so showed over four seven segments diode display.

Here electrical device R1 and electrical capacitor C1 area unit won’t to set the frequency of internal clock of ICL7107. Electrical capacitor C2 filters the fluctuations in internal reference voltage and provides stable reading on seven phase 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 be set the reference voltage for internal ADC.
This circuit includes four Common Anode Seven phase light-emitting diode 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've got conjointly have to be compelled to offer negative power to PIN twenty six of the ICL7107, that we've got used 555 IC. 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 to can’t get most negative voltage at the output. Here we've got used 100nF and 10uF.

Step 3: PCB Design Using Wellpcb

They recently launched their part sourcing service wherever they need an outsized stock of electronic parts and users will order their needed parts beside the PCB order.

Step 4: Calculating and Ordering Samples Online

After finishing the look of 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 is the PCB got from

Step 5: Below Are the Images After the Soldering of the Components on the Pcb: