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Open-circuit voltage (abbreviated as OCV or VOC) is the difference of electrical potential between two terminals of an
If we want to find the open-circuit voltage across the 5Ω 
Find the equivalent resistance in loop 1 to find the current in loop 1. Use Ohm’s law with that current to find the potential drop across the resistance C. Note that since no current is flowing through resistor B, there is no potential drop across it, so it does not affect the open-circuit voltage.
The open-circuit voltage is the potential drop across the resistance C, which is:
This is just an example. Many other ways can be used.
Open-circuit voltage (abbreviated as OCV or VOC) is the difference of electrical potential between two terminals of an electronic device
Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles. It is a subfield of physics and ...
when disconnected from any circuit. There is no external load connected. No external electric current
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge c ...
flows between the terminals. Alternatively, the open-circuit voltage may be thought of as the voltage that must be applied to a solar cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.
or a battery to stop the current. It is sometimes given the symbol Voc. In network analysis this voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...
is also known as the Thévenin voltage.
The open-circuit voltages of batteries and solar cells are often quoted under particular conditions (state-of-charge, illumination, temperature, etc.).
The potential difference mentioned for batteries and cells is usually the open-circuit voltage.
The value of the open-circuit voltage of a transducer
A transducer is a device that Energy transformation, converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another.
Transducers are often employed at the boundaries of automation, M ...
equals its electromotive force
In electromagnetism and electronics, electromotive force (also electromotance, abbreviated emf, denoted \mathcal) is an energy transfer to an electric circuit per unit of electric charge, measured in volts. Devices called electrical ''transducer ...
(emf), which is the maximum potential difference it can produce when not providing current.
Example
Consider the circuit:
If we want to find the open-circuit voltage across the 5Ω resistor
A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active e ...
, first disconnect it from the circuit:
Find the equivalent resistance in loop 1 to find the current in loop 1. Use Ohm’s law with that current to find the potential drop across the resistance C. Note that since no current is flowing through resistor B, there is no potential drop across it, so it does not affect the open-circuit voltage.
The open-circuit voltage is the potential drop across the resistance C, which is:
This is just an example. Many other ways can be used.
See also
*Electromotive force
In electromagnetism and electronics, electromotive force (also electromotance, abbreviated emf, denoted \mathcal) is an energy transfer to an electric circuit per unit of electric charge, measured in volts. Devices called electrical ''transducer ...
* Short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit ...
* Thevenin's Theorem
References
Electrical parameters {{Energy-stub