The particles that carry charge through wires in a circuit are mobile electrons. The electric field direction within a circuit is by definition the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field.

Electric current or electric charges flow because of the Coulomb’s force on them . The force is due to electric field. The field is created because of potential difference between two end points of a conductor.

electromotive force

To produce an electric current, three things are needed: a supply of electric charges (electrons) which are free to flow, some form of push to move the charges through the circuit and a pathway to carry the charges. The flow of electricity can be likened to a flow of water through a pipe.

Every circuit is comprised of three major components:

• a conductive “path,” such as wire, or printed etches on a circuit board;
• a “source” of electrical power, such as a battery or household wall outlet, and,
• a “load” that needs electrical power to operate, such as a lamp.

WHAT MAKES CURRENT FLOW IN A CIRCUIT? An electric current flows in a loop,powering bulbs or other electric COMPONENTS. A circuit is made up of various components linked together by wires. The current is driven around the circuit by a power source, such as a BATTERY.

However, electrical energy does not travel though the wire as sound travels through air but instead always travels in the space outside of the wires. This is because electric energy is composed of electric and magnetic fields which are created by the moving electrons, but which exist in the space surrounding the wires.

Answer: No. Electric current will not flow in a circuit in which there is a gap between them. This is because gap contains air and air does not conduct electricity.

A device designed to open or close a circuit under controlled conditions is called a switch. The terms “open” and “closed” refer to switches as well as entire circuits. An open switch is one without continuity: current cannot flow through it.

The definition of closed circuit is a system where video or other media is transmitted through connected cables and wires, not through the air. When you have a video camera directly connected to a TV on the property that shows images from the video camera, this is an example of a closed-circuit TV.

A closed circuit has a complete path for current to flow. This can happen when two bare wires in a circuit touch each other. The part of the circuit bypassed by the short circuit ceases to function, and a large amount of current could start to flow. This can generate a lot of heat in the wires and cause a fire.

parallel circuits

An intentionally open circuit would be the circuit to the lights in the room that are turned off. There is no closed path available for the electricity to flow to the lights because the switch is in the “off” position which “opens” the path the electricity would normally flow through.

To test for a live electrical wire either a non-contact voltage tester or a digital multimeter is used. A non-contact voltage tester is the safest way for testing live wires, performed by placing the machine near the wire.

To test for power with a non-contact voltage tester, touch the sensor tip of the tester to each of the circuit wires. If the tester lights up when touching any of the wires, the circuit still has power.

For testing the live wire without having the meter device, you can build your own tester. For example, get a socket and light bulb and attach a couple of wires to it, then touch one to the ground or neutral and another one wire to the test.

Tips for Identifying Wires in your Switch Wall Box

1. After removing the face plate, turn the breaker back on.
2. Very carefully, press the voltage pen against each wire.
3. The pen will glow red when the wire is hot.
4. The wire that causes the pen to glow red is the hot wire; also known as the Line wire.
5. The wire that does not cause the pen to glow red is the Load wire.

Briefly: To shut off the electrical power to your entire house, locate the main electrical panel (it pays to know where this is before you need it!) and flip the main circuit breakers at the top (usually a pair) to OFF. To shut off the power to individual rooms or circuits, shut off the branch circuit breakers.

To use a neon voltage tester, simply touch one tester probe to a hot wire, screw terminal, or outlet slot, and touch the other probe to a neutral or ground contact. The small neon bulb in the tip of the tool will light up if there is current present.

Many electrical incidents have occurred while qualified electrical workers were using a digital multimeter or test instrument. Shock hazards can occur if the meter and test leads are not properly maintained.

Safety Tips to Measuring Voltage With a Multimeter

1. Do not use your test leads if the protective insulation on the leads or probes is cracked or worn.
2. The movement of current from one hand to the other during an electric shock is the most dangerous.
3. Both DC and AC voltage can be very dangerous.

Multimeters are absolutely necessary for any type of electrical work. From installing a ceiling fan to changing a junction box, using a multimeter helps determine if wires are hot or not (and so much more). Multimeters are designed to measure three fundamental components of electrical energy: volts, amps and ohms.

As long as the probes are connected correctly to the voltage terminals and the meter range switch is set to volts AC you shouldn’t have any problems. Be very careful not to touch one probe end while the other is connected to mains.

1 Answer. Yes it is generally safe to use a multimeter to check the voltage on a wall outlet, but use caution on cheaper meters. When I plugged my meter, on AC voltmeter mode, into an outlet’s live and neutral, as well as live and ground, both times I received a reading of 239V on the screen.

Set a multimeter to measure voltage. Insert a probe into each slot and read the line voltage measurement. A properly working outlet gives a reading of 110 to 120 volts. If there is no reading, check the wiring and the outlet.