is a great addition to any Laboratory Power Supply
as it will measure the current consumption and help
you determine if there are any problems with the circuit
that you are building or testing. This amper meter
is capable of measuring the current consumption up
to 10A with selected 100mA, 10mA and 1mA accuracy,
and consumes only about 25mA of current. The ammeter
is based on single ICL7107 chip and 3.5-digit seven
segment LED display. Due to a relatively small number
of components that the circuit is using it is possible
to fit it on a small 3cm x 7cm printed circuit board.
Ohm resistor should be made out of 1.5mm thick / 5cm
long copper wire. 0.1 Ohm and 1 Ohm resistors should
have 5W ratings.
For highest accuracy it is recommended that the ICL7107
ampere meter module should be supplied with its own
voltage supply. If measurement of the current of the
same supply is needed, ICL7107 ampere meter would
have to sample negative not positive voltage supply.
Brightness of the LED displays can be varied by adding
or removing 1N4148 small signal diodes that are connected
in series. Use two 1N4148 diodes for higher brightness.
Also, the use of 7805 5V voltage regulator is highly
recommended to prevent the damage of ICL7107 and 7660
Dot on the seven segment LED display can be also moved
with addition of a dual switch as shown below.
100mA Resolution – 99.9 A
5A – 10mA Resolution – 9.99 A
2A – 1mA Resolution – 1.999
Use 10K potentiometer to set the reference
voltage between PIN 35 and PIN 36 of the ICL7107 IC
This PIC Volt Ampere Meter was designed to measure output voltage of 0-70V or 0-500V with 100mV resolution and 0-10A or more current with 10mA resolution. It is a perfect addition to any DIY laboratory power supply, battery chargers and other electronic projects where voltage and current consumption must be monitored. Thanks to added calibration via SETUP, UP & DOWN buttons it is now possible to calibrate the meter to measure voltage that is higher than 70V and current that is greater than 10A. More Info …