User Manual

ADC-20/ADC-24 Terminal Board User Guide Pico Technology
6 DO117-5
2.2 Current
You can use the ADC-20/ADC-24 Terminal Board with the ADC-20 or ADC-24 to
measure current. If the current returns through ground, you can use a simple shunt
resistor to convert the current into a voltage before measuring with the ADC. The
diagram below shows a circuit with a shunt resistor R
B
.
The locations for R
B
appear as R1b to R16b in the diagram of the terminal board at
the start of this booklet. You will need to calculate the resistor value R
B
from the
following equation:
MAX
RANGE
B
I
V
R =
where I
MAX
is the highest current you expect to measure and V
RANGE
is the selected
input range. (For example, if the ±625 mV range is selected, V
RANGE
is 625 mV.)
Warning!
Under no circumstances use this method for measuring mains currents.
Seek professional advice!
R
B
R
ADC
AG
0 V
V
IN
V
ADC
ADC
-
20/
ADC
-
24
u
nit
ADC-20/
ADC-24
terminal
board
Shunt resistor circuit
Channel