● push button switch types

How Push Button Switches Are Classified

Search for "push button switch" and you will see terms like momentary, latching, illuminated, metal, anti-vandal and emergency stop used side by side as if they were competing categories. They are not. They answer four different questions:

• Operation mode – What do the contacts do when you press and when you release? (Momentary vs. Latching)
• Illumination – Does the button give visual feedback, and what does the light mean? (Illuminated vs. non-illuminated)
• Material and structure – What is the housing made of, and what environment can it handle? (Metal vs. Plastic)
• Function and safety role – Is it an ordinary command device or a safety device? (Standard operator vs. Emergency Stop)

This guide walks through each of the five product families you will find in the CDOE catalogue using those four angles, then compares them in a single table and finishes with a selection checklist you can work through item by item.

1. Momentary Push Button Switches

A momentary push button switch is defined by what happens after your finger leaves it: the contacts return to their rest state immediately.

How do the contacts change when pressed?

Inside the switch a spring holds the contact block in its rest position. Pressing the actuator moves the block so that a normally open (NO) contact closes or a normally closed (NC) contact opens. Many CDOE models combine both in one body, written as 1NO1NC or 2NO2NC, so a single button can simultaneously send a "go" signal to one circuit and interrupt another.

Does it return to its original state when released?

Yes, always. The spring pushes the actuator back and the contacts resume their NO or NC rest state. The electrical signal lasts exactly as long as the mechanical press. This is why momentary buttons are sometimes called "reset" or "self-resetting" switches in product titles.

Which tasks need "act while pressed, return when released"?

• Machine start, cycle start and reset commands that a PLC reads as a pulse
• Jog or inching control on conveyors and axes, where motion must stop the moment the operator lets go
• Doorbells, horn buttons and call buttons (CDOE offers doorbell and horn symbol heads for these)
• Triggering a function on EV charging stations, vending machines and test equipment

Momentary models from CDOE span 10mm to 30mm mounting holes, 3A to 20A contact ratings (the 20A high-current series is a separate product line), and IP65 to IP68 front protection.

2. Latching Push Button Switches

A latching push button switch is the direct opposite of a momentary one on a single point: the contacts stay in the new state after you release the button. Everything else—NO/NC configuration, size, LED options, housing—can be identical.

Does the state hold after operation?

Yes. Pressing the button mechanically locks the actuator in the actuated position, and the contacts remain switched until the lock is deliberately released. In product listings this appears as "latching", "self-locking", "maintained" or "keep type".

How is a latching switch released?

This is where a common oversimplification causes ordering mistakes. Not every latching button is "press once for ON, press again for OFF". Three release mechanisms are common, and the datasheet of each model specifies which one applies:

• Push-push (alternate action) – a second press releases the lock. Typical for power ON/OFF on equipment panels.
• Twist release (rotary reset) – the head must be rotated to unlock. Used on many stop and emergency stop heads so an accidental second press cannot release it.
• Key release – a key must be inserted and turned. Used where only authorised personnel may restore the state.

Latching push buttons suit power switches, mode selection (manual/auto), lighting circuits and any state the operator should set once and see maintained. CDOE 16mm, 19mm and 22mm latching models are available in stainless steel or plastic, with or without ring LED, and in 12V/24V/220V illumination versions.

3. Metal Push Button Switches (and When Plastic Is the Better Choice)

Material does not change how a push button switches. A metal push button switch can be momentary or latching, lit or unlit. What changes is how it survives its environment and how it looks on the panel.

Which metals are used for the housing and bezel?

• Stainless steel – the default for anti-vandal and outdoor use; resists corrosion and scratching.
• Nickel-plated brass – good machinability and conductivity for the grounding path, with a bright finish.
• Anodized / electroplated aluminum alloy – lighter than steel, available in black oxide and colored finishes.
• Zinc-aluminum alloy – used for die-cast mushroom heads and some emergency stop heads.

Surface finish and appearance

Metal bezels are offered in natural brushed, polished, black oxide and electroplated colors. Head shapes include flat, domed, high (protruding) and ball heads. Ring LED and power-symbol LED illumination are cut into the actuator so the metal surface stays flush and cleanable.

Is anti-vandal design needed?

If the panel is accessible to the public—access control, kiosks, EV chargers, elevators, outdoor machinery—a stainless steel anti-vandal push button with a flat or recessed actuator and a one-piece body resists hammer blows, prying and weather. For an enclosed control cabinet used only by trained operators, this robustness is usually unnecessary cost.

Which environmental parameters to verify

Material alone does not guarantee suitability. Check in the datasheet: front IP rating (IP65, IP67 or IP68), operating temperature range (CDOE metal series are typically rated around -25°C to +65°C), salt spray or corrosion resistance if applicable, mechanical life in cycles, and whether the body is grounded through the panel.

Plastic push button switches

CDOE's 16mm, 19mm and 22mm plastic series use an environmentally friendly PC housing with a PBT base. Compared with metal they offer:

• Lower cost and weight – important on high-volume appliances and OEM panels.
• Electrical insulation – no conductive bezel to ground or isolate.
• Color-coding – red, green, yellow, blue, white and black heads moulded in color rather than painted.
• Head interchangeability – in the LA38 series, plastic (KA) and metal (KB) heads share the same contact base, so a panel can be upgraded later without rewiring.

Choose plastic when the switch lives inside a cabinet, on household or medical equipment, or in a dry indoor environment where impact and vandalism are not concerns. Choose metal when the switch is exposed, outdoors, publicly accessible or part of the product's premium appearance.

4. Emergency Stop Push Button Switches

An emergency stop push button switch (E-stop) is a safety device, not a styling option. It belongs in its own category because its purpose, mechanics and wiring differ from an operating button, even though both may be red and 22mm.

How does it differ from an ordinary stop button?

• It has a red mushroom head, usually on a yellow background or with a yellow warning ring, so it can be struck with a palm from any angle.
• It uses NC contacts with direct opening action: the operator's force physically separates the contacts; it does not rely on a spring to open them.
• It latches mechanically when actuated. An ordinary stop button is momentary and returns as soon as it is released.
• It is intended only for emergencies, not for normal cycle stop.

How does it hold the triggered state?

When struck, the head locks in the depressed position and the NC contacts stay open. The machine cannot be restarted simply by letting go or by someone bumping the button again. The latched head is also a visible signal that an emergency stop was triggered.

How is it reset?

Reset must be a deliberate manual action at the device itself. CDOE emergency stop switches use twist (rotary) release as standard, with key release versions where restart authority must be controlled. Some models offer pull-to-release. The reset method is specified per model and should match your risk assessment.

Why does the whole safety control system matter?

The E-stop button is only the input device. Its NC contacts should feed a safety relay or safety controller that de-energises the hazardous actuators. Two points from CDOE's emergency stop application notes deserve attention:

• Emergency stop input – Use the NC contacts (often two NC channels, 2NC or 1NO1NC) so that a broken wire or a dislodged contact block is detected as a stop, not as "all clear". The NO contact, if fitted, is for signalling and indication only.
• Restart inhibition – Resetting the E-stop button must not restart the machine. The safety circuit should remain in the stop state until a separate, deliberate restart command is given from the normal start control. This requirement is written into IEC 60204-1 and ISO 13850, and it is implemented in the control logic, not in the button.

CDOE supplies E-stop switches in the LA38 series (10A/660V) and the K20 series (20A/400V), with aluminum alloy heads for 16mm, 19mm and 22mm holes, PC plastic heads for 16mm and 22mm, regular, extra large and extra small head sizes, and a metal IP67 version with a bi-color strip LED that changes with switch state. Accessories include protective covers and yellow warning rings. Verify the model's safety rating, mechanical life and contact certification against your machine's safety design rather than ordering by appearance alone.

5. Mushroom Head Push Button Switches

A mushroom head push button switch has an oversized domed actuator that is wider than the body. The shape makes it easy to hit with the palm, the back of the hand or a gloved fist without aiming.

The important distinction: not every mushroom head is an emergency stop. The mushroom shape is also used for:

• Momentary start or stop commands on presses, conveyors and packaging lines, typically with a green or black head and 1NO or 1NO1NC contacts. CDOE's 22mm green mushroom head momentary switch (IP65) is an example.
• Illuminated mushroom heads where a dot LED or ring LED shows readiness, such as the 16mm zinc-aluminum alloy mushroom head with 9V/12V dot LED.
• Latching mushroom heads for maintained stop without full E-stop function.

Only when the head is red, the mechanism latches, reset is manual (twist or key) and the NC contacts are wired into a safety circuit does the mushroom head become an emergency stop. Treat the shape as an ergonomic choice and the function as a separate specification.

Push Button Switch Comparison by Classification Dimension

The table maps each product family against the four dimensions. Where a cell says "either", the product family exists in both forms and the model number decides.

How to Choose the Right Push Button Switch: A Checklist

Rather than restating the definitions above, work through these questions for each position on your panel. Each answer narrows the catalogue; together they identify a specific model number. For a deeper treatment of sizes, voltages and IP ratings, see the CDOE push button selection guide.

1. What operation mode does the task need?
   Does the command last only while pressed (momentary), or must the state hold until someone changes it (latching)? If latching, which release method—push-push, twist or key—fits the risk of accidental release?
2. What visual feedback is required?
   Should the button be lit at all? If yes, what is the light meant to say: power available, function active, fault, or "press me"? Does it need one color or a bi-color/tri-color LED driven by the controller? Confirm the LED voltage separately from the contact rating.
3. Where will it be installed?
   Check the panel cut-out (12, 16, 19, 22 or 30mm), panel thickness, depth behind the panel, and whether the terminal type (pin, screw, solder or wired connector) suits your wiring. Then check environment: front IP rating, operating temperature, exposure to chemicals or UV, and whether the switch is reachable by the public (anti-vandal metal) or sits inside a cabinet (plastic is adequate).
4. What circuit will it switch?
   Identify the control voltage and current. Match the NO/NC configuration to the logic: NO for start/trigger, NC for stop/safety, 1NO1NC when one button must do both. Compare the model's rated current and voltage (for example 3A, 5A, 10A/660V, 20A/400V) against the actual circuit. Read the datasheet of the target model—two switches that look identical can have different contact blocks.
5. Is this a safety function such as emergency stop?
   If yes, stop treating it as a button purchase. Confirm the E-stop requirements of your machine's safety design: number of NC channels, reset method, required performance level, mounting location and the restart-inhibition logic in the safety relay or controller. Do not substitute a general-purpose latching red button for an emergency stop, and do not accept a "universal equivalent" without checking it against the safety specification.
6. What about volume, consistency and certification?
   For OEM panels, confirm the manufacturer can supply the same model consistently with UL, CE, TUV, RoHS and REACH documentation, and whether custom heads, symbols or logos are needed.

Treat the list as a specification to be filled in, not as a conclusion. The right switch is the one whose datasheet satisfies every line for your specific installation.

Summary

Momentary and latching describe what the contacts do after release. Illuminated describes feedback. Metal and plastic describe the housing and its environment. Emergency stop describes a safety role with its own mechanical and wiring rules, and a mushroom head is an ergonomic shape that may or may not carry that role. Specify each dimension separately, confirm the result against the model datasheet, and involve the safety design whenever an E-stop is in scope.