The digital voltmeter ICL7107CPL

Here is my lovingly-crafted schematic for the voltmeter module. Note that this could be made as a standalone voltmeter, it will measure up to 20v DC. In our finished product, the +5V will be sourced from an LM78L05 voltage regulator.

And the parts list:

    IC1 – Intersil ICL7107CPLZ
    IC2 – Intersil ICL7660
    D1~D3 – 1N4148 diodes
    LED displays – Agilent HDSP521G 2 x 7-segment green displays (common anode). You can use anything really, as long as it is common anode, and each segment is ~8mA
    R1 – 220 ohm – all resistors 0.25W
    R2 – 10k ohm
    R3 – 1M ohm
    R4 – 47k ohm
    R5 – 15k ohm
    R6 – 100k ohm
    R7 – 1k ohm multiturn potentiometer/trimpot (for calibration)
    C1 – 10nF – all capacitors must be rated for at least 25V
    C2 – 20nF
    C3 – 470 nF
    C4 – 100 nF
    C5 – 100 pF
    C6,7 – 10 uF electrolytic

Please note that this is a work in progress and errors may have been made, or values altered at any time after publication.