4) Given the circuit below. The voltage is 5 volts and each
resistor is 10 ohms. The current flowing through the circuit (when
measured by an ideal ammeter) is 1 amp.
a) Show current through the circuit is 1 A.
Next, assume you put a DMM (in ammeter mode) which has a
resistance of one ohm at point A. Recalculate the equivalent
resistance of the circuit.
b) What is the current flowing through the circuit now.
This is the current reading the DMM will give as flowing into the
junction indicated by the arrow. Is it still 1 A?
Move the DMM to measure I1.
c) The resistance through the top branch is now 11 ohms
(resistor + ammeter). Calculate the new current.
You now move ammeter to measure the I2 . There is no need to
redo calculation since current will now be the same as calculated
for I1 since both resistors are the same.
d) Is the measured current into the (indicated) junction
the same as the sum of the currents measured out of the
Resistors Connected in Parallel Energised by a Battery