1. Problem # 3.36
A shunt resistor and a 50mV, 1 mA d’Arsenval movement are used to build a 5A ammeter. A resistance of 20 mΩ is placed across the terminals of the ammeter. What is the new full-scale range of the ammeter?
ECE 201 Circuit Theory 1

2. Imeasured = 5A
Ishunt = 4999 mA
ECE 201 Circuit Theory 1

3. Problem # 3.36
RA =20 mΩ
ECE 201 Circuit Theory 1

4. The meter is modified by placing a 20mΩ resistor in parallel with the existing 0.01Ω resistor.
ECE 201 Circuit Theory 1

5. Ifs
1 mA
Ish
6.67 mΩ
ECE 201 Circuit Theory 1