Electronic Components List with Images

Let us introduce you to the basics of all common electronic components through images and short explanations. Electronic circuits comprise many smaller components. If we do not know what each component does, it becomes impossible to build an electronic circuit with them.

All electronic components have at least two terminals (also known as leads or pins). These terminals are made of a conductive material. These leads are used to connect or solder components to each other to form a circuit.

In this article, we provide an overview of the most common electronic components, which include resistors, capacitors, diodes, transistors, LEDs, integrated circuits (ICs), and more. Further reading on each component is available via the links in the relevant section. Let us begin!

Electronic Components List

Resistors—resist the flow of electricity

The main function of resistors is to resist or reduce currents passing through them. Resistors are one of the most common electronic components. They are used everywhere, from household electronic appliances to industrial machines.

Resistors often have a small cylindrical shape with two wire leads coming out from both ends. They would also have color bands running across their body; these bands indicate each resistor value, also known as resistance — or how resistive to current it is. 

However, the higher wattage ones may come in the form of white rectangular blocks with text written on them.

Some of the resistor’s notable applications include:

• Divide the voltage into smaller voltages.
• Reduce the current passing through loads.
• Increase the time required to change a capacitor and speed up its discharge.
• Control the gain of the electronic amplifier.
  

Here are further readings on resistors:

• What is a resistor and color code?
• Resistors Symbol

Trimmer Potentiometers — An Adjustable Form of Resistors

Potentiometers — also known as trimmers or trimpots — are a variant of a resistor that allows for easily adjustable resistance. A potentiometer may have one extra lead compared to a normal resistor. Its resistance is usually adjusted via rotating a physical knob.

Capacitors—store an electrical charge

They have many uses. For example

• Store an electrical charge
• To smooth a fluctuating Signal
• Block continuous current while passing current pulses

Read Also

• Capacitor Principle working, types, and how it works
• Uses of capacitors | RC circuit time constant and Coupling

Capacitors have many types and sizes. We often use these three types of capacitors: Ceramic, Mylar, and Electrolytic.

• The Electrolytic has a lot of capacitance shown on its body.
  Importance! It is a polarised capacitor, therefore it has a positive and negative lead.
  Its negative lead (have a mark on it and a shorter lead) must always connect to the negative voltage.
• The Ceramic and Mylar have less capacitance than the Electrolytic. They are often very small compare to the Electrolytic ones. Therefore, there is a capacitance code on them instead.
  Capacitance code calculator:
  For example, 104J is 0.1μF on 5% tolerance.

  

  • First and Second Digit are fixed numbers, both numbers tell units in pF
  • The third digit is multiplied by the number of the power of ten.
    For example 10⁴ = 10,000
  • Fourth is tolerance level such as J = 5%, K = 10%, M = 20%.

    How to do it

    What is the 104K capacitor value?
    10pF — First and Second Digit
    10pF x 10⁴ = 100,000 pF. Which is 0.1μF and 10% tolerance.
  • First and Second Digit are fixed numbers, both numbers tell units in pF
  • The third digit is multiplied by the number of the power of ten.
    For example 10⁴ = 10,000
  • Fourth is tolerance level such as J = 5%, K = 10%, M = 20%.

    How to do it

    What is the 104K capacitor value?
    10pF — First and Second Digit
    10pF x 10⁴ = 100,000 pF. Which is 0.1μF and 10% tolerance.
  • First and Second Digit are fixed numbers, both numbers tell units in pF
  • The third digit is multiplied by the number of the power of ten.
    For example 10⁴ = 10,000
  • Fourth is tolerance level such as J = 5%, K = 10%, M = 20%.

    How to do it

    What is the 104K capacitor value?
    10pF — First and Second Digit
    10pF x 10⁴ = 100,000 pF. Which is 0.1μF and 10% tolerance.
  • First and Second Digit are fixed numbers, both numbers tell units in pF
  • The third digit is multiplied by the number of the power of ten.
    For example 10⁴ = 10,000
  • Fourth is tolerance level such as J = 5%, K = 10%, M = 20%.

    How to do it

    What is the 104K capacitor value?
    10pF — First and Second Digit
    10pF x 10⁴ = 100,000 pF. Which is 0.1μF and 10% tolerance.
  • First and Second Digit are fixed numbers, both numbers tell units in pF
  • The third digit is multiplied by the number of the power of ten.
    For example 10⁴ = 10,000
  • Fourth is tolerance level such as J = 5%, K = 10%, M = 20%.

    How to do it

    What is the 104K capacitor value?
    10pF — First and Second Digit
    10pF x 10⁴ = 100,000 pF. Which is 0.1μF and 10% tolerance.

Capacitors list

But deciphering the above might be too complicated. So my daughter put together a list of capacitors that we had seen:

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Diodes — A One-Way Valve for Electrical Current

Diodes are another common electrical component. They act as a one-way valve for currents, letting currents pass in one direction but not the other.

A common diode usually has a cylindrical body similar to a resistor. There is also a single stripe on the body indicating the cathode (K) lead. While the numbers indicate the diode’s model.

A diode possesses two terminals, labeled as cathode (K) and anode (A). Current can flow from anode to cathode (A → K ✅), but not from cathode to anode (K → A ❎). When current can flow through a diode, it is known as forward bias, while when it cannot, it is known as reverse bias.

A diode also has many uses, but it is often used for the following:

• Rectify current (converting AC to DC).
  
• Control the direction of current.
  
• Protect against reverse voltage.
  
• Clamp or offset alternating current (AC).

Diodes have different sizes and usage according to their spec. Their number will be printed on its body. As illustrated above is a diode that we often use.

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LEDs — A Diode That Emits Light

LEDs (light-emitting diodes) are — as the name suggests — a type of diode that emits light. Nowadays, LEDs are the most popular form of electrical lighting. 

Similar to diodes, LEDs need to be connected in the correct polarity (forward bias) for current to pass through. Their negative lead (or cathode, indicated by the shorter lead or a flat spot on the body) needs to be connected to the ground (GND). 

After the current flows through the LED in the correct polarity (forward bias), it will light up. In the case that the LED is connected in the wrong polarity (reverse bias), current cannot pass, and it will not light up.

LEDs typically possess higher efficiency than the alternatives, such as incandescent or fluorescent lamps. They also consume little power and have long lifespans. Moreover, they are available in many colors as well as invisible light, like infrared (IR) or ultraviolet (UV).

LEDs are used in all forms of lighting, including but not limited to:

• Low-power table or reading lamps.
  
• Battery-powered flashlight.
  
• High-intensity spotlight or stagelight.
  
• 7-segment digital number display.

You can find more information about LEDs here:

• How to Use LEDs and Example LED Circuit

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Zener Diodes — Set a Constant Voltage

Zener diodes — like the LEDs — are yet another variant of diodes. They share the same looks as and work similarly to a normal diode. 

When connecting a Zener diode in the correct polarity (forward bias), it allows current to pass through (anode → cathode). On the other hand, when connecting a Zener diode in the opposite polarity (reverse bias), current cannot pass through, just like a normal diode. 

However, if the voltage across a Zener diode exceeds a certain voltage threshold, it will allow current to pass through, even in reverse bias.

This voltage threshold is known as Zener diode voltage (VZ) or breakdown voltage. Each Zener diode has its own manufacturer-rated breakdown voltage, and it is constant and non-changing. Because of that, we often use a Zener diode’s VZ to set or regulate a constant voltage.

You can learn more about a Zener diode here:

• What is Zener Diode: How it Works & Example Usage

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Transistors—make an amplifier or switching circuit

Transistors are semiconductor electronic components with three leads or terminals. They function in a similar way to a switch, but instead of pushing a button or pulling a lever, transistors are controlled by electrical current.

Usually, a minuscule amount of current at the base (B) lead can control a much larger amount of current that flows from the collector (C) to the emitter (E) leads.

A transistor, as you might expect, can be found in all kinds of electronic devices, from computer chips to small phone chargers and more. Here are some examples of applications where we have used transistors:

• A signal amplifier circuit.
  
• A switching-mode power supply.
  
• An electronic switch.
  
• A logic component (logic gate).

All transistors can be put into two main groups. The first group is the NPN type; almost everyone prefers this type because it works with positive voltage. The other group is the PNP types; they work with negative voltage.

Transistors have many different shapes, according to usage characteristics. Their number will be printed on their body.

Read more about transistors here:

• How Does a Transistor Circuit Work? (Simple Guide + Diagrams)
• Transistor as Switch Experiment
• Experiment with Parallel Transistors for More Current
• How to Use a Transistor as a Soft Switch or Variable Resistor
• Small Signal Amplifier Circuit Using Transistor

Look at transistors that we use often.

My daughter often has problems with these tiny transistors because they look the same. But the position of their legs is different. It may cause the circuit to malfunction or be damaged. Therefore, we must always pay attention to its number.

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ICs — A Circuit Integrated Within One Package

ICs (integrated circuits) are electronic components with many other connected components (circuits) inside of them. The IC is a circuit integrated into a single package, sometimes called a chip.

An IC may be labeled and identified with a 3- to 5-digit number, usually printed on the body. Most also have some letters before or after the number; they usually denote the manufacturer or a sub-variant of the chip. ICs with the same number have identical functions.

An IC usually has many leads (also known as pins) that we use to connect to the circuit inside of the chip. And since an IC is just a functional circuit, there are numerous types of ICs, each tailored to a specific application or job. Many different types of ICs include:

• Power supply and regulator ICs — 7805, LM317, LM350, and TL431.
  
• Logic ICs (logic gates, sequential logic devices, or counters — CD4026, CD4017, and CD4069.
  
• Oscillator, multivibrator, or function generator ICs — ICL8038, CD4046, LM324, LM741, and NE555.
  
• Switch ICs — CD4066.
  
• Driver or controller ICs — ULN2003.

Above are a few popular examples; in reality, there are many, many more types and models of ICs. 

Another thing of note is the IC’s package type. The most common for the DIY space is DIP (dual in-line package). It is usually referred to by ‘DIP’ followed by a number indicating the pins (DIP8 for DIP with 8 pins). 

There is also a metal can package (such as a TO-99), usually an OP-AMP IC. It is a high-quality model while being relatively expensive. 

You can learn more about ICs here:

• Popular ICs for DIY Electronics – Datasheets & Circuit Examples

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SCRs—Silicon-Controlled-Rectifiers

The SCR is similar to a bipolar transistor. But its symbol is similar to a diode with having three legs.

It acts as a barrier to prevent electricity from flowing through the Anode (A) to the Cathode (K). Until there is a control current to trigger the Gate (G).

But electricity can not flow backward from the Cathode to Anode.

They have the symbol and shape as the above picture.

Read more: How SCR works and using

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Triac—two SCRs connected in parallel

Triac acts similar to an SCR. But it allows both directions of currents to flow through MT1 and MT2 if it has proper current control through Gate (G).

Therefore, they are good at an AC switching controller. They have symbols and shapes as illustrated below.

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DIAC — Two Zener Diodes in Parallel

DIACs (diode for alternating current) work similarly to a Zener diode. They do not conduct current until the voltage across them reaches a certain level. But unlike a Zener diode that only functions this way when reverse-biased, a DIAC possesses this characteristic both ways around.

In other words, a DIAC is like a Zener diode that does not have a forward bias; instead, it has two reverse biases. It does not allow current to pass in both directions if its voltage does not exceed the threshold. But it will if the voltage exceeds the threshold; it works in a bi-directional way.

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Relay — Electrically-Controlled Physical Switch

Relays are electromagnetic switches that require a small trigger current to operate. The trigger current passes through the relay coil, generating a magnetic field that pulls one physical switch contact against or away from another.

We can think of a relay as a switch that — instead of us pushing the contact to close or open the circuit — uses an electromagnet to push or pull the switch contact for us. It is also indicated in the symbol, which consists of an inductor coil adjacent to a switch with two stationary contact pads and a single movable one in the middle.

Relays are widely used today, despite being a very ancient technology. They are used in applications ranging from household water pumps to high-current industrial plants.

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Resettable Fuse — Protect Against Overcurrent Using Temperature

Resettable fuses (polymeric positive temperature coefficient devices, or PPTC) have the same basic function as a normal electronic fuse. They prevent current from passing when the value is greater than the fuse rating.

Cr: by uxcell
It looks like a capacitor, but it is a great fuse.

And see a poly switch symbol.

A normal fuse deals with overcurrent by physically blowing, creating an opening in the circuit, and preventing current from circulating, which means that it is a one-time-use device.

A resettable fuse is different, however. When the current increases, the fuse would heat up, and the higher the fuse’s temperature, the higher its resistance. 

Therefore, its chain of working can be summed up as the following: high current → high temperature → high resistance → reducing the current. Eventually, the current settles at the point at which the temperature and the resistance are stable. 

A resettable fuse would not immediately open (turn off) the circuit when faced with overcurrent; instead, it will increase its resistance until the current settles at a sustainable point. This means that it is reusable. Also, since the temperature is a direct cause of its resistance, we can use the resettable as a form of thermistor.

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