Ammeter
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 ampere 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.
0.01 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 ICs.
Dot on the seven segment LED display can be also moved with addition of a dual switch as shown below.
10A - 100mA Resolution - 99.9 A
5A - 10mA Resolution - 9.99 A
2A - 1mA Resolution - 1.999 A
great info about ampere meter thanks for sharing this.
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