Push Button (Tactile Switch)Momentary SPST-NO tactile switch

Press to connect, release to open.

Manufacturer-referenced

Omron · B3F-1000

6 × 6 mmOmron B3F Tactile Switch, Cat. No. A070-E1-08

A push button is a momentary switch: its contacts close only while the plunger is held down, and a spring opens them again on release. Tactile switches like the Omron B3F add a snap dome, so the press is felt as a click at a defined force. The B3F is made for logic signals, not loads: 1–50 mA at 3–24 V DC (resistive). Closed, the contact measures at most 100 mΩ at first; open, more than 100 MΩ. A microcontroller reads it through a pull-up resistor, and because the contacts bounce for up to 5 ms the program or an RC filter must ignore the first few milliseconds after each edge. This page covers the 6 × 6 mm B3F-1000 and the 12 × 12 mm B3F-4000, the two push buttons in ProTech. Each has four leads but only two contacts: the two leads joined across the body form terminal 1, the other two terminal 2. The page, ProTech and the KiCad footprints number them 1 and 2.

Real View

Omron B3F-1000 6 by 6 mm tactile switch: black body under a metal cover, ivory round plunger and four formed leads on a 6.5 by 4.5 mm pattern.

Pinout

B3F-10006 × 6 mmTop view · pads 1 joined across the body, pads 2 joined across the body

PCB Footprint

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3D View

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2Physical pins B3F-10006 × 6 mm Manufacturer-referencedOmron

Pin diagram

Select a pin to explore its connection

Package map

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B3F-10006 × 6 mmTop view · pads 1 joined across the body, pads 2 joined across the body

Click a lead or use the arrow keys. Top view · pads 1 joined across the body, pads 2 joined across the body

PIN 1 · Switch contact

1

Contact terminal 1

Function

Pads 1: two leads on opposite sides of the body (6.5 mm apart on the 6 mm switch, 12.5 mm on the 12 mm one), joined inside.

How to connect

Connect to the microcontroller input; with INPUT_PULLUP the input idles HIGH.

Electrical note

A switch has no polarity: terminals 1 and 2 may be swapped.

Key specifications

Wire one terminal to the input and the other to ground, give the input a pull-up, and the pin reads HIGH until the button is pressed. Keep the current within 50 mA: a tactile switch signals, a transistor or relay switches the load.

Contact rating50 mA at 24 V DC maximum, resistive · logic signals

Contact resistance100 mΩ maximum, initial · open > 100 MΩ

Contact bounce≤ 5 ms · debounce in software or with RC

Life1–3 M operations · 6 mm / 12 mm

Operating profile

Supply, signals and operating conditions

Push Button (Tactile Switch) operating profile
Parameter	Value	Conditions / notes
Selected package	6 × 6 mm	B3F-1000 · 4 leads, 2 contacts
Contact	SPST-NO	Momentary: closed only while pressed
Example circuit	5 V · 10 kΩ	0.5 mA when pressed · reads LOW

Package details

B3F-1000 · 6 × 6 mm

Selected package

Selected Push Button (Tactile Switch) physical package
Property	Details
Manufacturer	Omron
Part number	B3F-1000
Package	6 × 6 mm
Connections	2 pins
Mounting	Through-hole
Lead pitch	6.50 × 4.50 mm pad spacing
Package code	push-6mm
Thermal reference	Contact heating at the rating: (50 mA)² × 100 mΩ = 250 µW

Selected parts and terminals

Manufacturer scope and page conventions

Manufacturer specifications 6 parameters

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Parameter	Value	Conditions / notes
Reference parts	Omron B3F-1000 (6 × 6 mm) · B3F-4000 (12 × 12 mm)	Omron B3F Tactile Switch, Cat. No. A070-E1-08
Contact form	SPST-NO, momentary	Closed only while the plunger is held
Leads	4 leads, 2 contacts	The two leads across the body are joined inside
Terminal 1	Pads 1 (two leads)	ProTech pin 1 · KiCad pad 1
Terminal 2	Pads 2 (two leads)	ProTech pin 2 · KiCad pad 2
Proteus symbol	BUTTON	2 pins; ProTech’s Push Button models it

If unsure which leads are joined, measure: the pair that reads 0 Ω unpressed is one terminal.

The two push buttons

From each manufacturer’s sheet · the numbers ProTech’s model and checks use

Manufacturer specifications 13 parameters

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Specification	Omron B3F-1000	Omron B3F-4000
Contact rating (resistive)	1–50 mA at 3–24 V DC (resistive)	1–50 mA at 3–24 V DC (resistive)
Minimum load	10 µA at 1 V DC	10 µA at 1 V DC
Contact resistance	100 mΩ maximum (initial)	100 mΩ maximum (initial)
Insulation resistance	≥ 100 MΩ at 250 V DC	≥ 100 MΩ at 250 V DC
Dielectric strength	500 V AC for 1 min	500 V AC for 1 min
Operation	0.98 ± 0.29 N (100 gf); release ≥ 0.2 N	1.27 ± 0.49 N (130 gf); release ≥ 0.29 N
Travel	pretravel 0.25 mm	pretravel 0.3 mm
Life	1 000 000 operations	3 000 000 operations
Contact bounce	≤ 5 ms	≤ 5 ms
Operating temperature	−25 to +70 °C	−25 to +70 °C
Size	6 × 6 mm, plunger Ø3.5 mm, 4.3 mm high	12 × 12 mm, plunger Ø7.1 mm, 4.3 mm high
Terminals	6.5 × 4.5 mm (4 leads)	12.5 × 5.0 mm (4 leads)
Look	black body, metal cover with four tabs, ivory round plunger	black body, metal cover, large ivory round plunger

Contact resistance is the initial maximum; it rises with wear and contamination. Ratings are for resistive loads.

How ProTech models it

The same numbers drive the simulator, its checks and this page

Manufacturer specifications 6 parameters

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Parameter	Value	Conditions / notes
Closed	100 mΩ between pins 1 and 2	I = V / Rc, P = I² · Rc
Open	No branch	Insulation resistance not modelled
Rating check	Warns above 50 mA or 24 V	Pop-up Check page and the status bar
Bounce	5 ms in the Lab only	Not in the running circuit
Modes	NO (closed while pressed) · NC (open while pressed)	Properties; latching keeps its saved position
Size	Drawn at true size	6 × 6 mm or 12 × 12 mm against the Uno

Change the switch in Properties: the drawing, rating, contact resistance and PCB footprint follow it.

Reading it with a microcontroller

5 V input with a pull-up resistor

Manufacturer specifications 6 parameters

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Parameter	Value	Conditions / notes
Pull-up	10 kΩ to 5 V (or INPUT_PULLUP)	Input idles HIGH
Pressed current	0.5 mA	5 V / 10 kΩ, far below 50 mA
Pressed voltage at the pin	≈ 50 µV	0.5 mA × 100 mΩ contact resistance
Contact heating	0.025 µW	(0.5 mA)² × 100 mΩ
RC debounce	10 kΩ + 100 nF → τ = 1 ms	Settles within about 5 τ = 5 ms, the bounce time
Software debounce	Read again 10–20 ms after an edge	Longer than the 5 ms bounce

Never switch a motor or lamp through a tactile switch: let it drive a transistor or relay.

Package

B3F-1000 · 6 × 6 mm

Manufacturer specifications 5 parameters

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Parameter	Value	Conditions / notes
6 mm body	6 × 6 mm, plunger Ø3.5 mm, 4.3 mm high	B3F-1000
12 mm body	12 × 12 mm, plunger Ø7.1 mm, 4.3 mm high	B3F-4000
6 mm pads	6.50 × 4.50 mm pad spacing, Ø1.1 mm drill	KiCad SW_PUSH_6mm
12 mm pads	12.50 × 5.00 mm pad spacing, Ø1.2 mm drill	KiCad SW_PUSH_12mm
Mount	Through-hole	Leads soldered; the plunger faces up

Footprints are KiCad’s, the same as ProTech’s PCB page; check the drill against your board house.

Connections by function

Select a pin for its function, connection guidance and electrical notes.

Switch contact2 pins

Push Button (Tactile Switch) working principle: illustrated functional stages, basic circuit and connections — Select the diagram to read it at full resolution.

How it works

3 stages · Explore one step at a time

Step 1 / 3

Released: the dome holds the contacts apart

A small metal dome sits over the fixed contacts. Unpressed, it does not touch the centre contact, so terminals 1 and 2 are open (insulation ≥ 100 MΩ).

Step 2 / 3

Pressed: the dome snaps and closes the circuit

At about 0.98 ± 0.29 N (100 gf) the dome snaps through with the click you feel, and its centre lands on the inner contact: terminal 1 meets terminal 2 through at most 100 mΩ.

Step 3 / 3

The contacts bounce, then settle

Metal on metal rebounds a few times before it rests. For up to 5 ms the input may see several edges; a debounce delay or an RC filter turns them into one.

Push Button (Tactile Switch) in a circuit

5 V, a 10 kΩ pull-up, the button to ground.

INPUT_PULLUP replaces the external resistor with the chip’s own.

Connect it, step by step

Follow the component values and pin connections

Pull the input up

10 kΩ to 5 V (or INPUT_PULLUP) makes the pin read HIGH while the button is open.

Button to ground

Pressed, the button shorts the pin to ground: it reads LOW, and 0.5 mA flows.

Debounce

Ignore edges for 10–20 ms after the first, or add 100 nF across the button.

Cutaway of a tactile switch: two leads joined as terminal 1 to the outer contacts, terminal 2 to the centre contact, a metal snap dome above them and the plunger on top; released and pressed views. — Functional cutaway; proportions simplified.

Explore the circuit

Select a stage to see its role and connections

Two terminals, four leads

Each terminal has two leads joined by a strip in the base; the four legs only hold the switch firmly.

The snap dome

Pressing flattens the dome past its tipping point: the click, and the contact.

Return

Released, the dome springs back and lifts the plunger: the contact opens again.

Selected package6 × 6 mmB3F-1000

Physical connections2 pinsPackage-specific numbering

Reference collection6 tables36 parameters & pin functions