The three basic elements used in electronic circuits are resistors, capacitors and inductors. Each of them plays an important role in the behavior of an electronic circuit. They also have their own standard symbols and units of measurement.
What is Resistors?
A resistor represents a certain amount of resistance in a circuit. Resistance is a measure of how much it is against or “against” the flow of current. It is defined by Ohm’s Law which states that resistance is equal to voltage divided by current.
Resistance = voltage/current
or
R = V/I
Resistance is measured in Ohms. The Ohm is often represented by the omega symbol: Ω.
What is Capacitors?
A capacitor represents the amount of capacitance in a circuit. Capacitance is the ability of a component to store an electrical charge. You can think of it as the “ability” to store an electrical charge. Power is determined by the equation
C = q/V
where q is the charge in coulombs and V is the voltage.
In a DC circuit, a capacitor becomes an open circuit preventing any DC current from passing through the capacitor. Only alternating current flows through the capacitor.
Capacitance is measured in Farads.
The capacity symbol consists of two parallel lines. Sometimes one of the lines is bent as shown below. The letter “C” is used in the equations.
What is Inductors?
Inductance represents the amount of inductance in the circuit. Inductance is the ability of a component to produce an electromotive force due to a change in current. A simple inductor is made by looping a conductor through a coil. Inductors are used in electronic circuits to reduce or counteract the variation of current.
In a DC circuit, the inductor looks like a wire. It has no effect when the current is constant. Inductance is only effective when the current changes, as in an AC circuit.
Inductance is measured in Henrys.
The symbol of the inductor is a series of coils as shown below. The letter “L” is used in the equations.
Interesting Facts about Resistors, Capacitors, and Inductors
The resistance of a material is the opposite or inverse of the electrical conductivity.
Ohm is named after the German physicist Georg Ohm.
Farad is named after British physicist Michael Faraday.
Henry is named after the American scientist Joseph Henry.
Combinations of capacitors, inductors, and resistors are used to construct passive filters that only allow electronic signals of a certain frequency to pass through.