Electrical units and how they are measured

• Current is electron flow, measured in amps (A) or milliamps (mA). Use an ammeter in series.
• Voltage is the pushing force, measured in volts (V) or millivolts (mV). Use a voltmeter in parallel.
• Resistance restricts current, measured in ohms (Ω), kilohms (kΩ), or megaohms (MΩ). Use an ohmmeter/multimeter.
• Ohm's law is V=ꞮR (Voltage = Current × Resistance).
• Multimeters measure V, Ɪ, R. Connect for voltage (parallel), current (series), resistance (circuit off). Start high, work down.

1. Current (flow of electrons)
   Amp (A) = big current (like in a kettle)
   Milliamp (mA) = tiny current (like in LED)
   1000mA = 1A
   Measurement Tool: Ammeter, connected in series with the circuit.

2. Voltage (pushing force)
   Volt (V) = normal battery voltage (like 9V battery)
   Millivolt (mV) = tiny voltage
   1000mV = 1V
   Measurement Tool: Voltmeter, connected in parallel with the component.

3. Resistance (restricts flow)
   Ohm (Ω) = small resistance
   Kilohm (kΩ) = thousand ohms
   Megaohm (MΩ) = million ohms
   Measurement Tool: Ohmmeter or multimeter.

A multimeter is a versatile tool that can be used to measure voltage, current, and resistance in electrical circuits. It combines several measurement functions into one device, making it essential for diagnosing and troubleshooting electrical systems.

Ohm’s Law describes the relationship between voltage (V), current (Ɪ), and resistance (R) in an electrical circuit.

The law states that:
Voltage = Current × Resistance
or
V=ꞮR

If you know any two of these quantities, you can calculate the third.

The formula can be rearranged as follows: