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Simple Definitions

The most important electronics terms, demystified in one place.


Our Take

Voltage is the measure of electromotive force across an object, basically telling us how much the electrons want to move from one point to another. Due to this, you don’t measure voltage *through* an object, you measure *across* an object, because you measure how much desire there is for the electrons to get from one side across to the other side.

There is also a longstanding debate on whether or not it’s voltage or current that is dangerous and we’re taking the stance of it’s both. It’s the current that kills but you can’t have current without voltage. But depending on the circumstances, a high voltage can be very safe while at other times, if there is low resistance, it is very dangerous. That’s why it’s complicated and that’s why people refuse to agree on things.

Book Definition

Potential difference - the energy required to move a unit charge through an element, measured in volts.

Fundamentals of Electric Circuits, 5th Edition by Charles K. Alexander and Matthew N. O. Sadiku

Ability of electric charge to do work in moving another charge. Measured in volt units.

Grob’s Basic Electronics, 11th Edition by Mitchel E. Schultz


Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points. The difference in electric potential between two points (i.e., voltage) in a static electric field is defined as the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage is named volt.[1] In SI units, work per unit charge is expressed as joules per coulomb, where 1 volt = 1 joule (of work) per 1 coulomb (of charge). The official SI definition for volt uses power and current, where 1 volt = 1 watt (of power) per 1 ampere (of current).[1] This definition is equivalent to the more commonly used 'joules per coulomb'. Voltage or electric potential difference is denoted symbolically by ∆V, but more often simply as V, for instance in the context of Ohm's or Kirchhoff's circuit laws.

Electric potential differences between points can be caused by electric charge, by electric current through a magnetic field, by time-varying magnetic fields, or some combination of these three.[2][3] A voltmeter can be used to measure the voltage (or potential difference) between two points in a system; often a common reference potential such as the ground of the system is used as one of the points. A voltage may represent either a source of energy (electromotive force) or lost, used, or stored energy (potential drop).

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