Active components vs passive components is one interesting topic to know and yet very useful for us in the beginner topics of electrical engineering. For those who have learnt this topic can’t deny that this topic is important in advanced analysis.
Both active and passive components in electronics are required to build a complete circuit. We need both to:
- Deliver energy,
- Absorb energy,
- Convert energy, and
- Control energy
We can differentiate electronic components into many types, but the only one matter is between active vs passive components.
There are several factors to determine which one is an active component and which one is a passive component. We can list few of them:
- Functions and applications,
- Behavior towards energy,
- Resistances or impedances,
- Voltage, current, and power characteristics,
- Etc.
What is an Active Component
An active component is:
- Capable for delivering energy to the circuit,
- Producing energy in the form of voltage or current,
- Able to generate power gain (can act as an amplifier),
- Control the current flow in the circuit, and
- External source is required to operate.
The most common examples of active electronics components are a voltage source, current source, transistor (and all types of transistor), IC, amplifier, and every power electronic device.
An active component is mainly used to control the electron flow in the circuit. Having active components in electronics is a must to energize an electrical circuit. Voltage source or current source is a must to use to energize a circuit.
Voltage source has the duty to supply the circuit with specified voltage no matter how much current is drawn. A battery is a basic example of a voltage source.
Current source has the duty to supply the circuit with specified current no matter how much voltage is needed.
Transistor is different from voltage source and current source because it can’t produce energy on its own. Transistor still has one characteristic of an active element, that is to amplify power. Thus it needs external sources to operate and control.
What is a Passive Component
A passive component is:
- Capable for absorbing energy in the circuit,
- Storing energy in the form of voltage or current,
- Unable to generate power gain (can’t act as an amplifier),
- Unable to control the current flow in the circuit, and
- External source is not required to operate.
The most common example of electronic passive components is resistor, capacitor, inductor, diodes, and every circuit load.
A passive component is mainly used as a load in the circuit. This component only knows how to absorb energy in the circuit thus it can’t control the flow of electrons. The absorbed energy is stored in a magnetic or electric field.
Having passive components in electronics is also a must. Passive components can reduce the current flowing in the circuit to prevent any faults.
Just as the opposite of an active component, this component is unable to produce any power gain or electrical signals.
Resistor absorbs energy in the circuit and converts it into heat as long as current flows through it.
Inductor absorbs energy in the circuit and stores it into a magnetic field. The stored energy can be delivered to the circuit but not on a continuous basis. This energy is very limited and not stable so we can ignore it in most cases.
Capacitor absorbs energy in the circuit and stores it into an electric field. The stored energy can be delivered to the circuit but not on a continuous basis. This energy is very limited and not stable so we can ignore it in most cases. But unlike inductors, capacitors can supply small voltage in a short time when the source is cut off so the circuit is not immediately turned off.
Active Components vs Passive Components
We can list several differences between active and passive components, but the fundamental difference between active vs passive components is the conservation of energy.
Energy can’t be created or destroyed, it can only be converted into another form of energy.
An active component is capable of using small energy to control larger energy in the circuit. Unlike passive components where it only absorbs and converts energy into another form.
This is why we need external sources for active components because we need something to control.
After we have learned about what is an active component and passive component, we can compare those two to remember them better.
Characteristic
- Active: capable of generating and controlling electrical energy in the circuit.
- Passive: incapable of generating and controlling electrical energy in the circuit.
Role
- Active: generating and controlling energy in the circuit.
- Passive: absorbing and converting energy in the circuit.
Electric current
- Active: capable of generating, controlling, and amplifying electric current.
- Passive: capable of absorbing and storing electric current.
Function
- Active: nonlinear and bilateral components.
- Passive: linear and unilateral components.
Electrical energy
- Active: energy generator.
- Passive: energy receiver.
Examples
- Active: source, transistor, integrated circuit.
- Passive: resistor, inductor, capacitor.
Power gain
- Active: capable of amplifying power in the circuit.
- Passive: incapable of amplifying power in the circuit.
External source
- Active: external source is needed to control power in the circuit.
- Passive: external source is not needed to control power in the circuit.
