Different Types of Electrical Switches & Their Application

Ed Combs
By Ed Combs
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Whether a seasoned electrician or a budding electrical enthusiast, we can all agree that the world of electrical switches can be dizzying. There are innumerable types of electronic switches available, each suitable for different functions and applications - even industries. From rocker switches to toggles or SPSTs to DPDTs - it's like learning a new language.

However, understanding the language is critical to success, regardless of application. So, how do you determine which switch is appropriate? After all, the wrong selection can result in a blown fuse or worse.

It’s time to demystify these switches, which are less complicated than they appear. Understanding electrical switches can be eye-opening, lending confidence to selection and ensuring proper application function. For example, certain types of switches can actually offer control over an electrical load from multiple locations, opening up application possibilities you probably hadn't even considered.

Today, we’re explaining what you need to know about electrical switches in straightforward language  - call it getting back to the basics. Think of this guide as your friendly neighborhood electrician popping over for a chat – except we're not charging by the hour.

By explaining each switch type's purpose and potential uses without jargon overload, we'll empower you to make that perfect selection confidently. Ready to get to know electrical switches better than ever before? Let’s begin.

Key Takeaways

  • Electrical switches let us control the flow of electricity in devices and systems.
  • There are many types of switches like toggle, slide, push button, limit, and float switches for different uses.
  • Mechanical switches include SPST and DPDT and are used for many applications, from simple on-off tasks to controlling multiple circuits.
  • Electronic switches such as MOSFETs and IGBTs manage power in modern electronic applications.
  • Specialized semiconductor devices like bipolar transistors and triacs help control high-voltage circuits efficiently.

Understanding Electrical Switches

Before deep diving into the many switch types available, let's unpack their core, i.e., definition and function. After all, these critical electrical components control power and underscore every electronic application, shaping how we harness energy in countless devices and systems around us.

Definition and Function

Electrical switches play a vital role in our daily lives. They control the flow of electricity and let us turn devices on or off. For example, when we flick a light switch, we're opening or closing an electrical circuit.

This simple action can light up a room or cut power to an appliance.

Switches come in many shapes and sizes; however, their function is mostly the same - interrupting or continuing the flow of an electric current. Basically, switches ensure energy goes where it's needed and prevent it when it's not.

Using switches, we manage energy conservation and safely operate equipment in homes, cars, and workplaces. Simply put, every electrical and electronics application uses at least one switch to perform the ON and OFF operation of the device.

Types of Electrical Switches

There are many different kinds of electrical switches at work around us that help control power and make our devices work the way we want. Let’s explore:

  • Toggle Switches: These include light switches we flip up or down to turn lights on or off. They have a lever that moves over a pivot.
  • Slide Switches: With these, you slide a knob or handle across a track to switch circuits on or off.
  • Push Button Switches: Pressing these opens or closes an electric circuit. Releasing them returns them to their original position.
  • Limit Switches: Machines often use these. A movable arm is bumped by another object, which makes the switch change its position.
  • Flow Switches: These switches notice when air or liquid starts moving in pipes and react accordingly.
  • Float Switches: They have a floating device that triggers a switch, which can set off alarms or control pumps based on water level changes.

Mechanical Switches

Let’s begin with mechanical switches, the backbone of traditional switching applications. These robust devices physically connect or disconnect circuits to control power flow with a reassuring click that many of us associate with reliability and manual control. This video helps explain the types and working principles of common mechanical switches used in electrical and electronic circuits, providing helpful real-world examples of applications.

SPST, SPDT, DPST, DPDT, Rotary Switches

We often use different types of mechanical switches in our daily lives. Each type has its unique function for controlling power and circuits.

  • SPST (Single Pole, Single Throw): This is the simplest kind of switch with one input and one output line. It's like an on-off switch for a single circuit and is found in basic appliances like table lamps.
  • SPDT (Single Pole, Double Throw): This switch has one input and two outputs, so it lets you direct current to one of two paths. They're perfect for switching between two circuits, like a fan and a light.
  • DPST (Double Pole, Single Throw): This switch controls two inputs connected to one output each. It can turn off or on two lines simultaneously with a single action. This type is usually found where you need to control two separate circuits together, like turning off all parts of a heavy appliance
  • DPDT (Double Pole, Double Throw): These are more complex, consisting of two inputs connecting to two outputs. You can control multiple functions or devices with this switch. For example, a car signal indicator uses DPDT, so both the front and the back indicators are activated when the indicator switch is turned on. These switches are great for reversing the direction of motors or switching between different power sources
  • Rotary Switches: With these, you can control several circuits using just one knob. They let you select different settings like voltage levels by rotating the switch to various positions (like with a variable speed fan). Their flexibility makes them suitable for devices where many options are needed from one control point.

Selector Switches, Intermediate Switches

Selector switches and intermediate switches need us to touch them to work. They play unique roles in electrical setups. Selector switches let us pick different settings, and they can turn equipment on or off. For example, you can find selector switches on control panels or machines for various functions, and they are often a knob or a lever.

Intermediate switches, often called three-way or crossover switches, are used with particular light circuits, as they can connect three or more switches to one light. Basically, when you have three or more light switches used to control one lamp, the middle switch of the three must be an intermediate switch. 

An intermediate switch is very useful when you want to power the lights in the entire area using a single switch, such as in large rooms or hallways because it manages the flow from multiple points. Intermediate switches can also be used like a dimmer switch to control the brightness of your lights from several areas.

Electronic Switches

On the other end of the spectrum from mechanical switches are electronic switches. Unlike mechanical switches, electronic switches do not require any physical contact to control a circuit. These are activated by semiconductor action. Electronic switches are integral to circuit operation and vary from tactile push buttons that offer immediate feedback to slide switches that gracefully transition between states, each designed for specific applications and control. Let’s explore the most common different types of electronic switches used across various applications.

Toggle Switches

Toggle switches are simple to use and found in many places. You flip the lever up or down, turning a device on or off. They come in several types, like SPST and DPDT, depending on the different needs of the application.

We often see toggle switches in homes as light control switches. Their design makes them easy to operate with just a finger flick. Whether you need a single-pole switch for basic tasks or a double-pole for more complex circuits, toggle switches have you covered.

Slide Switches

Slide switches are simple to use and integral to many electronic devices. They have a slider that moves back and forth to connect or disconnect the circuit. This action lets electricity flow when in the ON position and stops when switched OFF. Slide switches come in handy for lights, small machines, and various consumer electronics like radios, televisions, and video game consoles.

SPDT slide switches are often used to control the current in equipment. They're great because they can switch between two circuits with just a slider move. These kinds of slide switches help us save space on our devices because they do the job of two separate switches!

Push Button Switches

Push button switches are also easy to use and seen in many everyday items. With a simple press, the switch's spring mechanism completes or breaks the circuit. This action turns electrical devices on or off quickly - such as with doorbells and machinery controls.

Peerless Electronics stocks various push button switches for different needs. Whether you need a standard push button switch for a DIY project or something more specialized for industrial use, Peerless Electronics’ online inventory includes options that can fit almost any application.

Limit Switches

We see limit switches in action daily, like in our washing machines. They detect if something is there or not, helping to keep the machine's moving parts from going too far. For example, garage doors use limit switches to detect objects in their way. This smart control can help stop accidents and keep objects and people safe in many situations.

In factories and other places where people work with big machinery, limit switches are imperative for safety. For example, when a conveyor belt moves products, a limit switch ensures everything stops before anything can get damaged or cause harm.

These small but mighty tools take care of us without us even knowing it, making sure equipment only goes as far as it should.

Flow Switches

Flow switches play a big role in monitoring liquids and gasses. They have a metal arm that moves when enough air or liquid goes through pipes or ducts. This action quickly activates the contacts, which helps control systems stay safe and work right.

In factories, flow switches are vital for monitoring pressure in machines that use fluids or air. The switch reacts fast to stop damage or leaks if the flow is too low or too high. These devices help ensure hydraulic pumps and air tools operate smoothly without problems.

Float Switches

Float switches turn on and off as liquid levels rise or fall. These switches have a float mechanism that moves with the changing water levels in tanks and sumps. We see them often in our homes, keeping basements from flooding by controlling sump pumps. In industrial settings, these switches help manage large-scale processes by making sure liquids stay at safe levels.

These devices are all about buoyancy; they float on top of the liquid and activate a switch when it's time to take action. For example, a float switch can trigger an alarm or start a pump to lower the level if water gets too high. It’s a great example of using technology to keep everything running smoothly without having to manually check liquid levels all the time.

Pressure Switches

Pressure switches keep an eye on fluid or gas pressure and jump into action if it gets too high or low. These handy devices help stop damage to machines by turning them on or off when needed. Pressure switches ensure everything runs smoothly and no part of the system gets overworked. Pressure switches play a key role in many kinds of equipment, from air compressors to boilers.

Pressure switches are invaluable for determining precisely when the pressure hits a certain point. This precision helps industries keep their systems safe and efficient. For example, if a machine's pressure goes off track in a factory, a pressure switch will immediately notice and fix the problem, keeping workers and machinery out of harm's way.

Temperature and Thermal Switches

Temperature and thermal switches keep our machines from getting too hot. They use a special part called a bimetallic strip, which bends when it gets warm. Similar to how a curve in a road changes the way you drive, the bimetallic strip bend changes the function of devices when it senses heat to keep operations safe. 

These switches are smart about heat. They know exactly when to cut off the current before any damage happens. Whether in coffee makers or engines, these switches are always on guard, ready to act fast if things get too warm.

Timer Switches

We use timer switches to control lights, heaters, and other devices automatically. These switches save energy by turning things on or off at set times without us needing to remember.

A timer switch is perfect for outdoor lighting that needs to be turned on at night and off in the morning. They also help with heating systems to make sure our homes are warm when we get there.

Timer switches come in different styles, including mechanical, digital, and programmable. We can set them once for daily routines - and adjust them anytime as needed. This makes life easier because our electrical devices work on their own.

Using a digital timer switch lets us program multiple ON/OFF schedules for more complex needs. With these smart tools, we can manage our electricity better and reduce waste.

Semiconductor Switching Devices

Next up are semiconductor switching devices, which are compact components that harness the properties of semiconductor materials to control power - critical to a vast array of applications from smartphones to space stations. 

Bipolar Transistors

Bipolar transistors are essential for quick switching and amplifying device tasks. These come in two main types: NPN and PNP, each with unique properties. NPN transistors use a small current to control a larger one and make things work like radios or computer parts. However, PNP transistors are used when we need the current flow to go the opposite way. 

Bipolar transistors have three parts: collector, emitter, and base. Think of them as two diodes back-to-back with the ability to switch on or off or even amplify signals in your gadget's circuits. The main difference between the two types of transistors is that holes are the more critical carriers for PNP transistors, whereas electrons are the essential carriers for NPN transistors. 

MOSFET

MOSFET or Metal Oxide Silicon Field Effect Transistors is a voltage-controlled four-terminal device that is used in circuits for switching and amplification purposes. They have three main parts - drain, source, and gate - which work together to manage electronic signals quickly and accurately. 

One of the most common applications of MOSFETs is as switches in power electronics circuits. A MOSFET can switch on and off very fast, allowing it to handle high frequencies and reduce power losses. Additionally, it can handle high currents and voltages, which makes it suitable for high-power applications.

SCR

We often turn to silicon-controlled rectifiers, or SCRs, when we need a reliable way to control high-voltage AC power. These devices ensure electrical currents flow smoothly in one direction at the right time.

SCRs are highly suitable for applications where precision and efficiency matter. That's why you'll find them in advanced motor drives for both alternating current (AC) and direct current (DC). They manage motors with a finesse that helps heavy machinery operate smoothly or even delicate medical equipment run safely. Therefore, SCRs can tackle tough jobs in industries like manufacturing while also keeping sensitive processes under tight control.

IGBT

IGBT (Insulated Gate Bipolar Transistor) is key in handling high-voltage circuits. This device combines the simple gate-drive characteristics of MOSFETs with the high-current and low-saturation-voltage capability of bipolar transistors.

IGBTs control electric power in many industrial, commercial, and energy applications. Thanks to fast switching speed capabilities and minimal saturation voltage characteristics, IGBTs are extensively employed for commercial applications like solar energy harnessing units and uninterruptible power supply (UPS). In consumer electronics, you can find them used for temperature control with induction heater cooktops or digital camera stroboscopes.

GTO

GTO stands for Gate Turn Off Thyristor. It’s a semiconductor-based, fully controlled unidirectional switching device with three terminals: Gate, Cathode, and Anode. A unique feature of the GTO is that it can be turned ON and OFF by using the same gate terminal.

We use GTOs to control the power in AC and DC motor drives because they can handle large amounts of electricity quickly and efficiently.

GTOs can turn off large currents swiftly, ensuring smooth operation whether you're working on industrial machinery or advanced electric vehicles.

DIAC

DIAC (DIode for Alternating Current) is a semiconductor switching device that has the ability to conduct electricity in both directions once it hits a certain voltage. This makes the DIAC an excellent choice for managing how much power goes into things like motor speed controllers and heat control circuits.

We often use the DIAC with another device called a TRIAC to control alternating current (AC). In simple terms, you can think of the DIAC as a switch that waits patiently until the electric charge builds up enough to tell it to start working. Once this happens, it jumps into action, allowing current to flow through and do its job—like adjusting how fast an electric fan spins or controlling how warm an electric heater gets.

Triac

The TRIAC is a bidirectional switching device and an important member of the thyristor family of devices. TRIAC is an abbreviation for a TRIode AC switch where TRI means that the device consists of three terminals, and AC means that it controls the AC power, i.e., it can conduct in both directions of alternating current. 

Basically, TRIACs are designed to help adjust how much power goes through a circuit, which is why these semiconductor devices are critical to electronic equipment, where smooth power management is paramount. They are most often used in motor speed controllers, AC circuits, pressure control systems, light dimmers, and other AC control equipment.

Other Switching Devices

In addition to the numerous switches we've explored, we should mention a couple of other devices designed for specific functions within various circuits. These include the DIP (Dual In-line Package) switch, favored in digital technology settings, and relays, which allow a low-power signal to control a much higher-power circuit. Both are integral components in countless modern applications.

DIP

DIP switches stand for dual inline package switches because they hold several small switches in a neat row. We often use DIP switches on breadboards and printed circuit boards (PCBs), which are instrumental in setting configurations. For example, we can change address settings in computer memory or tweak input/output ports with the help of DIP switches.

With DIPs, customizing settings and making adjustments becomes simple and fast. They are highly useful in tech equipment because they make changing device behaviors easy without complex tools or software.

Relay

A relay is an electromagnetic switch that opens and closes circuits electro-mechanically or electronically. Relay switches use a small signal to control a high-voltage circuit, making them perfect for tasks requiring one signal to manage multiple circuits. For example, relays allow us to turn multiple lights on at once using one switch.

At Peerless Electronics, we understand the importance of reliable relays in critical fields like military and aerospace. That's why we stock a wide range of these devices from top manufacturers. Whether working on industrial machines or medical equipment, our extensive selection ensures you'll find the correct relay for your project.

Application of Electrical Switches

As we explore the vast array of electrical switches, understanding how they fit into everyday applications is illuminating and helpful. From controlling lights in homes to managing complex machinery in industrial settings, these devices are integral in countless systems, providing safety, efficiency, and convenience across various sectors. Next, learn how switches work in the world across various industries.

Industrial

In the industrial world, electrical switches are integral to the operation of heavy machinery and equipment that require sturdy controls like push-button switches, selector switches, intermediate switches, limit switches, flow switches, float switches, pressure switches, and temperature and thermal expansion-based switches.

They keep factories running smoothly by controlling motors or adjusting processes based on different conditions.

We offer a vast selection of these industrial-grade electrical components at Peerless Electronics, like rugged HONEYWELL AST products for harsh conditions or precision SAFRAN POWER USA items for exacting applications.

These high-quality switching devices ensure safety and efficiency in any industrial setting while fitting various budgets with competitive prices.

Commercial

Businesses need reliable electrical switches to run machines, lights, and computers in offices, stores, and restaurants. They control power to different areas with a simple flip or push, and Peerless Electronics has provided businesses with top-quality switches for decades. 

We are a trusted stocking distributor for leading switch manufacturers like HONEYWELL AST and SAFRAN POWER USA, LLC. These products meet the high demands of commercial environments. They ensure safety and efficiency in workplaces across various industries. Our extensive online inventory makes finding the right switch for any application straightforward.

Residential

In our homes, switches are everywhere. For example, single-pole switches are used to turn lights on and off, making them the most common switches found in residential settings.

However, there are numerous other types of switches at work around homes. For example, three-way switches are common in hallways and staircases, allowing control of a light from two locations, like the top and the bottom landings, for convenience and safety.

There are also push-button switches, which are used in many home devices like doorbells, and timer switches that help save energy by turning off lights or fans after a set time has passed.

Other applications include basements or sumps, where float switches monitor water levels and activate pumps when needed to prevent flooding, or temperature switches in our heating and cooling systems that kick into action to keep our living spaces comfortable no matter what it's like outside.

Automotive

Cars and trucks use a lot of different switches. We see toggle switches flick on the lights and feel pressure switches work under our feet when we brake. Every time you adjust your seat or check the gas level, there's a switch involved. They keep things running smoothly and make sure drivers can control their vehicles easily.

Peerless Electronics stocks many unique switches just for cars and trucks. From joystick controls for heavy machines to sensor-driven limit switches, we've got the parts that automotive experts trust.

Aerospace

In the aerospace world, switches play a crucial role in both control systems and safety. Aerospace applications often require special switches that can handle extreme conditions for high-speed operations, like those in radio-frequency ICs. For example, bipolar transistors are a common choice because they switch quickly, making them perfect for industry applications.

Our inventory at Peerless Electronics includes top-notch electrical switches from HONEYWELL AST and SAFRAN POWER USA, LLC, designed to meet the strict requirements of the aerospace industry.

From NPN transistors that act as electronic switches or amplifiers to PNP transistors with their three specific terminals, we provide components essential for creating reliable aerospace electronics.

Medical

We understand the critical role electrical switches play in medical devices. Our inventory includes specialized switches that ensure the safety and precision required in healthcare equipment.

For example, foot pedal switches actuated by doctors give them hands-free control during delicate procedures, and pressure switches are integral to monitoring patients' blood pressure, helping to save lives every day.

Peerless Electronics takes pride in supplying top-quality electrical components for medical applications. We offer a wide variety of options, like micro-switches that respond to tiny movements or temperature switches, ensuring instruments stay within safe operating ranges.

Trust is essential, so we make sure all our products meet strict industry standards for reliability and performance.

Conclusion

Electric switches make our lives easier and safer by facilitating control of eclectic flow in devices and systems used across countless residential, commercial, and industry-specific applications. Understanding all the many types available and how they apply to various applications, providing function and safety, is critical to making the right selection.

And when it comes to selection, Peerless Electonic’s online stock of switches is extensive. Whether you need switches for various industrial applications or need to meet the requirements of demanding Military / Aerospace and Defense applications - Peerless has your needs covered as a fully authorized source for today’s leading switch manufacturers - and every purchase is backed by our certified to AS9100 and ISO9001:2015 value-added services.

FAQs

1. What are the basic types of electrical switches?

The basic types of switches include single-pole, double-pole, three-way, and momentary switches. Each type is used for different applications, depending on the needs.

2. How do poles and throws work in a DPDT switch?

A Double Pole Double Throw (DPDT) switch controls two circuits with two options each (on-off). Poles refer to the number of separate circuits the switch can control, while throws indicate how many positions each circuit can connect to.

3. What is a micro switch, and where is it used?

A microswitch is a small electrically conductive switch that operates quickly with a little force. It's often found in appliances and machinery as part of logic circuits or safety mechanisms like turning off an electric motor if something goes wrong.

4. Can you explain what "normally open" and "normally closed" mean for switches?

“Normally open” means the electrical path isn't complete when the switch isn't pressed, so electricity flows once activated. “Normally closed” means electricity flows until the button is pushed, breaking the circuit.

5. Why would I use a three-way light switch in my house?

You'd use a three-way light dimmer or light switches to control lights from two locations, like both ends of a staircase or hallway, so you don’t have to walk back to turn off lights when crossing these areas.

6. Are there special types of diodes or transistors that act as switches in electronics?

Yes, devices like power MOSFETs, N-channel MOSFETs with threshold voltages, power diodes forward biased for current flow rate control, gate turn-off thyristors (GTO), p-channel devices for reverse polarity protection all function as specialized electronic switches within their respective roles.