12V Momentary Power Push Button Switch Aluminum Dome Latching

Hi i recently bought a 12v mementary power bush button to switch on my 12v portable dvr. I recently tested the power out is only 3.4v.. does anyone know if i need a relay or something to make it work?

by Azliza8676
September 26, 2018

In normal electronic speak, a momentary push button is ON only so long as you keep pressing it. To make it hold ON you need a latching relay. Wire it so that the button energises the coil and the contacts both turn on the output and the coil. switch it off by breaking the circuit.

by mikerogerswsm
September 27, 2018

Like this:


by mikerogerswsm
September 27, 2018

Hi sorry its a latching type sorry

by Azliza8676
September 27, 2018

The problem is the in is 12v but when latched it only give less then 3volts any ways to make it to boost to 12v when latched?

by Azliza8676
September 27, 2018


It has 4 pin

by Azliza8676
September 27, 2018

Your link shows an illuminated touch switch. Not sure what the connections are. Do you have the maker's name, or part number, or datasheet?

by mikerogerswsm
September 27, 2018

Is the latching mechanical (usual) or electronic (rare)? Are you sure of the connections? Two wires go to the switch and the other two to the led with/without current limiting resistor. My best guess is that you are using one or more of the led connections.

by mikerogerswsm
September 27, 2018

On viewing the datasheets for the ULV4 series of buttons most of them are SPDT and have five connections which are marked NO NC C for the SPDT switch and LED1 LED2 for the leds. The leds are two in anti-phase parallel with no current limiting resistor. Hope this helps. mike

by mikerogerswsm
September 28, 2018

Hi mike

Sadly it doesnt came with any instructions

Bought it here

16mm 12V Universal Car LED Light Momentary Power Push Button Switch Aluminum Dome Latching Type https://s.click.aliexpress.com/e/c0Rp08ik

by Azliza8676
September 29, 2018

Label the wires. With an ohmeter identify the two wires which are shorted together when the switch is ON and open when it is OFF. These are the switch wires. Connect them in your high side feed, The other two wires are the led. It should light up when you pass 20mA (ie about 470 ohms from 12V ) in one wire and out of the other or vice versa. Hope that makes sense. mike

by mikerogerswsm
September 29, 2018

1 Answer

Answer by mikerogerswsm

Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account

Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers

Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.

About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.