DC Fundamentals Unit 13 – Direct Current Meters
Exercise 1 – The DC Ammeter .................................................................................................
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to determine current by using a basic
meter movement. You will verify ammeter operation by measuring known values of current.
EXERCISE DISCUSSION
- The ammeter is an instrument that measures current and must be placed in series with the
circuit. Since this is a dc ammeter it must be connected with the correct polarity. - The amount of deflection depends on the amount of current flowing through the meter.
- This meter is rated at 1 mA full-scale; therefore, full-scale defection requires 1 mA of
current. - Current that exceeds the maximum meter rating is shunted away from the meter movement.
- Range of a meter can be increased if a resistor (RSHUNT) is placed in parallel with the meter
movement.