The multimeter or tester is a device that is able to measure different magnitudes and signals in an electrical circuit. The most common signals in a tester are: direct (DC) and alternating (AC) voltage, direct (DC) and alternating (AC) current and resistor.

 

 

Voltmeter

The voltmeter is used to measure the voltage or potential difference of the charge or source. Voltage exists between two points and does not flow through a circuit as occurs with current. The voltmeter is therefore connected in parallel between these two points.

Ohmmeter

The ohmmeter is an instrument used to measure the electrical resistor that appears in circuit or the resistors - components that make the circuit.

Ammeter

An ammeter must be connected to the circuit in series - in other words, you need to connect positive to positive or negative to negative. DC or AC types of ammeter are selected, depending on the type of current should be measured. DC ammeters must be connected to the circuit, observing the correct polarity.

The correct connection is shown on the following diagram. Inappropriately connection can damage components of the circuits.