1. Basic Instruments and Measurements
Chapter 2

2. Basic Analog Meter
D’Arsonval movement – stationary magnet, moving coil galvanometer.
Iron Vane Meter – two pieces of iron are placed inside a hollow core solenoid.
Current causes magnetic field to move a needle.
Extreme caution and care when handling an analog meter.
Proper polarity must be maintained

3. Meter Scales Linear meter scale – marks are evenly spaced.
Note what range the dial of meter is set to when reading the value of the scale.

4. Ammeter Measures electrical current in a circuit.
Amperes
Milliamperes
Microamperes
Shunt is used to direct excess current away from meter.
Always connected in Series with the circuit.

5. Voltmeter Measures electrical voltage present in a circuit:
Volts
Millivolts
Connected in Parallel with the circuit

6. Ohmmeters Measures the resistance of a device or part of a circuit:
Megaohms
Ohms
Milliohms
Microhms
Zero the meter
Battery inside the case used to measure resistance.

7. Other Meters Volt – Ohm – Milliammeter (VOM) Digital Multimeter (DMM)
Computer Display meters

8. Electrical Diagrams Schematics Wiring Diagrams
Symbols (see page 453 – 454)