How can electricity be detected and tested?

In an electrical circuit, there are many different components and different things that need to be measured. Some of the tools that can measure these various things will be specific to one measurement, but many will combine measurements into one tool. Things to measure include:

Current

Current is the flow of electricity and is measured in amperes (amps, A). A device that can measure current is known as an "ammeter". To measure current, the measuring device must be connected in series with the circuit so that the electrons pass through the ammeter at the same rate as they pass through the circuit.The current can be both direct and variable (constant or variable). This has to do with how the electrons move through the circuit, either directly; in one direction; or alternation; back and forth.

Potential difference (voltage)

Voltage is the potential difference between two points in a circuit and is provided by what we call the power source in the circuit; battery or wall socket (mains electricity). To measure voltage, you need to connect a device called a voltmeter in parallel with the circuit.

Resistance

Resistance is measured in ohms (ohms) and is related to how the material of a conductor allows current to flow through it. For example, a short cable has less resistance than a long cable because less material passes through it. A device that can measure resistance is called an ohmmeter.

Current, resistance and potential difference

There is a relationship between volts, amps and ohms in an electrical circuit. This is known as Ohm's law, represented by a triangle where V is voltage, R is resistance, and I is current. The equation for this relationship is: amps x ohms = volts. So if you have two dimensions, you will be able to calculate the other one.

Power supply

Power is measured in watts (W). In electrical terms, a watt is the work done when one ampere flows through one volt.

Polarity

Polarity is the orientation of the positive and negative points in a circuit. Technically, polarity only occurs in DC circuits, but since mains (AC) has one wire grounded, this creates hot (live) and neutral terminals on sockets and connections, which can be thought of as polarity. As a general rule, polarity is indicated on most items (eg batteries), but it may be necessary to check the polarity on some devices, such as speakers, where it has been skipped.Because polarity detection can involve distinguishing between positive and negative, and hot and neutral, there are several different tools that can check this, including voltage detectors and multimeters.

continuity

Continuity is the test of a circuit to determine if it is working or not. A continuity test indicates whether electricity can pass through the element being tested or if the circuit is broken in some way.

capacity

Capacitance is the ability of a cell to store a charge and is measured in farads (F) or microfarads (µF). A capacitor is a component added to a circuit to store charge.

frequency

Frequency occurs in AC circuits and is measured in hertz (Hz). Frequency is the number of oscillations of an alternating current. This means how many times the current changes direction per unit time.