The potential difference between two test points resulting from the distribution of charge in the circuit, usually measured in volts.


Net amount of charge (coulombs) (number of electrons x electron charge) flowing past a specified point during a time interval (seconds), usually measured in Amps (1 Amp = 1 coulomb / 1 second). In typical components and systems the quantity of electrons is quite large and the aggregate charge flow is referred to as electricity.


Energy given in a certain amount of time, usually measured in watts.


When potential difference creates movement of electrons between two points, some of the potential energy formerly available in the system is irreversibly transferred from the electric field or the electrons moving through the component via collisions with atoms and molecules within the material. Ohm’s Law, V=IR, defines resistance as R=V/I where V is the voltage difference applied across the component, I is the resulting current flow in Amps, and R is a constant created by characteristics of the component which is calculated from the measured voltage loss of the measured current passing through the component.

Electric Power Formula

Electric power is the rate at which energy is transferred to or from a part of an electric circuit. A battery can deliver energy, or a circuit element like a resistor can release energy as heat. For any circuit element, the power is equal to the voltage difference across the element multiplied by the current. By Ohm’s Law, V = IR, and so there are additional forms of the electric power formula for resistors. Power is measured in units of Watts (W), where a Watt is equal to a Joule per second (1 W = 1 J/s).
General form:
electric power = voltage difference x current
P = VI

P = electric power (W)
V = voltage difference
I = electric current
R = resistance

Short Circuit

Electronics Short.PNG

A short circuit is another name for a node, although it usually means an unintentional node. Has current through it but no voltage across it.

Open Circuit

Electronics Open.PNG

Has potential across it but no current through it.

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