When is the voltage directly proportional to the current

Components in the electrical circuit

Simple non-branched circuits

Ohm's law

In a circuit, two determine the third. If, for example, voltage and current are given, the resistance is calculated from them. Two electrical quantities are always required in order to be able to calculate the third. It is important to be able to predict the relationship between current, voltage and resistance. This is possible because the electrical resistance of a conductor (of course within physical limits) is constant. The first proof of this was provided by Mr. Ohm. That is why we refer to the mathematical relationship between these electrical quantities as Ohm's law.

Ohmic
law

Ohm's law describes the relationship between electrical voltage U, the electric current I. and the resistanceR. in a closed circuit.

The electrical resistance of a metallic conductor is independent of the strength of the electrical current. (Ohm's law)

How
and
Why
is
the
electricity
Tension
dependent

 

The cause of an electrical current is an electrical voltage.

A higher voltage also results in a higher current.
Current and voltage are therefore directly proportional to one another.

The resistance also determines the current. A large resistance value only allows a smaller current.
Current and resistance are therefore indirectly (inversely) proportional to one another.

In a closed circuit, with constant resistance, the current and voltage are directly proportional to each other.

That means: A higher voltage results in a higher current with the same resistance.

This can also be understood as follows: The same current causes a greater voltage drop at the greater resistance.

 

 

The
formula
With
greater
importance

 

U

tension

V.

volt

or

 

I.

electricity

A.

amp

 

R.

resistance

Ω

ohm

 

G

Conductance

S.

Siemens

Conductance

Instead of resistance R. can also with the conductance G be expected.

The electrical circuit is clearly defined when two of the three electrical quantities - current, voltage and resistance - are known.

   761018

Training workshop / electrical engineering / chap. 1/2