Passive and active components – examples, functionalities and differences
Passive and active components – examples, functionalities and differencesDate of publication: 28-11-2022 Update date: 20-04-2026 🕒 5 min read
- Passive or active component?
- Passive components – overview
- Active components – examples
- Are you keen on electronics? Visit Tech Master Event
Every electrical and electronic circuit can consist of a great many smaller components. They can perform most diverse functions, have different housings and dimensions – there are plenty of differences, however, each component can be passive or active, or wattless and live as they are also called sometimes.
Passive or active component?
A component category, i.e. active or passive, depends on its impact on electrical signals. Passive components can only consume and store energy. Active components, on the other hand, can exert impact on electrical signals, for example, by changing their parameters.
Passive components – overview
Resistors
A resistor is a classic example of a passive component. It limits the current flow to protect other components, e.g. LEDs, against damage. It means that a resistor only consumes energy, converting its excess into heat, without actively affecting electrical signals.
Fuse
All kinds of fuses, i.e. elements breaking an electrical circuit when too much current flows through it, are also passive components. These vital parts of electronic systems and equipment protect users against accidental electric shock and other system components against overvoltage and overload. Fuses vary in design, but the most common ones installed in all types of equipment, come with a fuse link. Similarly to resistors, these components do not affect electrical signals, but only consume energy when tripped and break a circuit.
Capacitor
Capacitors are components used as commonly as resistors. Their main function in DC circuits is to store electrical energy. Basing on our definition of passive components, it can be said without a shadow of a doubt that a capacitor is a passive component.
Coils
A coil is an inductive component comprising a winding wound on a core (usually a cylinder-shaped element), but there are also coreless coils, i.e. solenoids. An induction coil (or inductor) is another passive electronic component, as it does not affect electrical signals actively. In DC circuits, it is a purely resistive element, while in the case of currents with pulsation different from zero, it is characterised by its reactance, i.e. a capacitive-inductive parameter.
Ferrite
Ferrite filters are used in almost all common applications. They are usually installed within power supply or communication cables, including USB cables. Such filters are designed to attenuate undesirable high-frequency signals. A ferrite can also be considered as a passive component, as it is a combination of a coil, a capacitor and a resistor, i.e. other passive components.
Potentiometer
Potentiometers are also passive components. As a matter of fact, these are resistors with adjustable resistance values. Any excess energy in potentiometers is turned into heat.
Potentiometers available at TME
Varistors
A varistor is a resistor exhibiting a non-linear resistance characteristic depending on the actual voltage. In these bismuth-zinc components, the resistance decreases in line with increase in voltage, so they can be used as surge protectors. When a surge occurs, a varistor receives all the energy and protects the device by burning itself off. Varistors are also passive components, as they only draw energy.
Photoresistor
A photoresistor is just a resistor whose resistance is linked to the amount of light that illuminates it. It is a classic passive component, as it is similar to a standard resistor, and does not actively affect any electrical signals.
Photoresistors available at TME
Thermistor
A thermistor is another passive resistor, but its resistance is determined by a different parameter, i.e. temperature. A non-linear resistance characteristic is its differentiating feature, as it can alter resistance depending on temperature. This makes it suitable for applications requiring an element providing protection against excessive temperature increase.
Active components – examples
Transistors
A transistor is a classic example of an active component. This semiconductor element can be found in a very wide range of applications in electronic engineering. As it is an electronic component, its most important feature is its ability to amplify electrical signals. Thus, it can be characterised as an active component.
Operational amplifiers
An operational amplifier is another example of an active component. It is one of the most common analogue elements whose design amplifies the voltage applied to the input, which makes it an active component.
Operational amplifiers available at TME
Obviously, the above list is not exhaustive, as microprocessors and a variety of processors can also be considered active components comprising millions of transistors. Electron tubes, not so popular anymore, are also active components. Before transistors were invented, electron tubes had been commonly used to control and amplify electrical signals.
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Transfer Multisort Elektronik (TME) is one of the world’s largest global distributors of electronic components, electrotechnical parts, workshop equipment, and industrial automation. The catalog includes over 1,500,000 products from 1,300 leading manufacturers. TME’s modern logistics centers in Łódź and Rzgów (Poland), with a combined area of over 40,000 m², ship nearly 6,000 packages daily to customers in more than 150 countries.
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