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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?

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.

Like this:

https://www.circuitlab.com/editor/#?id=qyv456edgvsz

Hi sorry its a latching type sorry

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?

https://www.google.com/search?client=ms-android-samsung&biw=412&bih=416&tbm=isch&sa=1&ei=4ratW9HlIczxvgT7hL8I&ins=false&q=ulv4+button+switch&oq=ulv4+button+switch&gs_l=mobile-gws-wiz-img.3..30i10.34900.36336..38032...0.0..0.143.436.1j3......0....1.aXpuoc1q_Yw#imgdii=VY-rVvI8yWbEgM:&imgrc=C0W1NJ5ovlefTM:&isa=y

It has 4 pin

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?

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.

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

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

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

Like this: https://www.circuitlab.com/editor/#?id=qyv456edgvsz