Figure 1-20.Proper ammeter connections.
Connecting an ammeter in parallel would give you not only an incorrect measurement, it would also
damage the ammeter, because too much current would pass through the meter.
EFFECT ON CIRCUIT BEING MEASURED
The meter affects the circuit resistance and the circuit current. If R1 is removed from the circuit in
figure 1-19(A), the total circuit resistance is R2. Circuit current
with the meter (R1) in the circuit, circuit resistance is R1 + R2 and circuit current
The smaller the resistance of the meter (R1 ), the less it will affect the circuit being measured. (R1
represents the total resistance of the meter; not just the resistance of the meter movement.)