# Electrical Measurements

Measuring Potential Difference (Voltage)

Voltage is named after Alessandro Volta the Italian Physicist that built a rudimentary battery using different metals. He also noted that the nervous system in animals was driven by electricity. For this reason we also measure the size of the potential difference in Volts.

Voltage or potential can be considered to be the height that electricity falls through.

When measuring voltage the multimeter must be place parallel to the device with which you want to measure the voltage drop.

When we measure voltage the leads must go into the sockets marked V & COM Measuring Current;

Current is another matter, the common symbol for current is I, and to commemorate another European physicist Andres Ampere, from France, we measure current in Amps.

We need to measure current in series with the apparatus we want to know how much current goes through ...

When we measure Current the leads must go into the sockets marked mA & COM

measuring resistance (for metallic conductors)

When we measure Resistance the leads must go into the sockets marked V & COM

Multimeter is the modern way of measuring quantities about electricity around the circuit.

A multimeter is a device that can measure different quantities in electricity, such as Voltage, Current and Resistance.

Within the unit there are many circuits that allow the multimeter to carry out these measurements accurately.

There is a switch dial which you must ensure points at the quanitity that you want to measure

V = Voltage

A = Current

R = Resistance

When we are measuring any of these quantities we need to plug in 2 cables.

One of these cables / leads must go to the common!

(sometimes noted as COM)

If we are measuring Current (and expect a small current) we plug into the mA socket.

If we want to measure Voltage, we plug into the V socket. 