Questions relating systems powered by a 12 volt supply. This may include automotive systems and lead-acid batteries that are nominally 12 volts although be aware that under many conditions the actual voltage may be several volts higher.

learn more… | top users | synonyms

3
votes
1answer
77 views

How long can I run my camera off this battery?

I have Ultramax NP7-12 12v 7ah specifications here: http://www.batterymasters.co.uk/ProductDocs/SLAUMXNP7-12-TECH.pdf My camera consumes 1.25 watts per hour and runs at 7.8 volts but can run between ...
0
votes
0answers
21 views

Emulating, tricking or faking a liquid cooling sensor

I have a specialty server board with an attached liquid cooling system, the liquid cooler has 3 pins attached to the board, pin 1 gnd, pin 2 12v+, pin3 sense. I'm assuiming this works like a cpu fan. ...
0
votes
1answer
25 views

Clock / timer activated 2 second voltage timer for wiper motor project

Ok, I need a 12 volt voltage timer using clock or timer for a wiper motor. I am working on a project in my garage. Simply put, I am wanting to use a wiper motor that will open and close a spring held ...
-3
votes
0answers
61 views

Automotive 12V to 5V 3A looking to reduce to 5V 700ma (not duplicate, but thanks) [duplicate]

Not a duplicate question.....this is item specific. Out of the electronics scene for a while. I am looking for a 5V source, 700mah for an application to power my cellphone and also power the HDMI ...
1
vote
2answers
116 views

Two relays for DRL on a car

I am trying to make a circuit for my newly installed DRL (Day running lights), what I am trying to do is have the DRL run all the time, turn off when using high beam, dimmed when headlights are on. I ...
2
votes
2answers
81 views

Interfacing incompletely documented logic signal where resistor affects output voltage level

So I've got this marginally documented 12V logic signal from something I have to regard as a black box that I'd like to interface to a pi or arduino (i.e. c 3V). I have 3 lines - 0V, +12V and signal ...
0
votes
1answer
58 views

electrical fridge running on car battery [closed]

I'll be out of grid for some days and I'm planning to have a small electrical fridge with me. It's a 12V 4A small fridge with a cigar lighter plug, but I won't have a car with me, so I think I could ...
1
vote
1answer
139 views

12V LED strips in series with a 24V power supply?

I am purchasing 50x - 1Meter / 12V / 72 LED /Rigid SMD 5730 strips directly from china. I don't know the LED manufacturer, nor the resistor being used. (yes, this is a gamble) The strip is one that ...
-2
votes
1answer
41 views

12 v xbox connection [duplicate]

Hi again if I just want to connect my tv and x box360 to the mains I've got it connected to the van at no so the neg is to the body and pos is by the fuse box. Can I just wire the transformer neg to ...
0
votes
1answer
166 views

How to build a blinking 12V indicator LED light

I attempt to build a blinking circuit using 12V truck light ( like this one: http://www.princessauto.com/pal/en/Tail-Lights/4-in-LED-Stop-Turn-Tail-Light/8126047.p). I have try to build a single LED ...
0
votes
3answers
73 views

Need to cap voltage at 12V, and need to vary voltage down

I tried to find something like this in the knowledge base, but didn't see a perfect match. I have a small submersible pump. 12VDC, 4.8W. Model DC30a-1230. I assume that is 0.4amps. There seem to ...
1
vote
2answers
81 views

UPS 12V power switching

I was trying to make a sort of UPS circuit with a 12V DC 5Ah power supply and a 12V 5Ah seal-lead battery. My question is that I don't know how to switch quickly from line supply to battery. I've ...
1
vote
2answers
76 views

Messing with rgb leds and have a question

I have some LEDs that I'm wanting to use in a project. I would like to know what's the best resistor I would need to get the most light out of the 3 different colors using a 12v source. I've measured ...
-1
votes
1answer
186 views

Charging battery using computer power supply?

I have new 600W ATX computer power supply unit. I have wired green and black together to make power supply turn on when plugged in. I wanted to charge my 12VDC empty battery, without dealing damage to ...
1
vote
1answer
81 views

Best method to eliminate alternator whine from a 12V line?

I've purchased a Miccus Mini-Jack Rx BlueTooth audio receiver. This device will accept a bluetooth signal from my phone and output it to a headphone jack that I plug into the AUX-In on my car stereo. ...
1
vote
3answers
166 views

Best way to drop 12V fan to 7-9V? [closed]

So my Xbox one PSU died and microsoft doesn't sell official ones yet, so I bought a third party one and the fan that is in it is a 12V blower fan with 2 wires running right to the board (it says 12V ...
0
votes
1answer
95 views

Can I damage a device using opposite polarity? [closed]

I have a device that requires input of 12V DC with positive polarity and a power supply that outputs 12V DC negative polarity (see figures below). Can I plug it in to try to see if it's working or ...
0
votes
4answers
610 views

Why does my DIY “solar panel circuit” show battery voltage and not solar panel voltage?

I've got two solar panels set up in series as shown on the below schema. I connect positive on panel A to positive on battery, and negative on panel B to negative on battery. The two panels produce 9V ...
-1
votes
1answer
135 views

Why does one LED slightly influence the other parallel LED although controled by differenct MOSFET-N?

I created a simple circuit that turns on and off two 12VDC LED with signals from my Arduino Leonardo R3, which is powered by a 5V USB cable from my PC. The LEDs are attached to a dedicated 12V power ...
2
votes
3answers
292 views

Triple output power supply

I need to power my device with three different voltages: 3.3V, 5V and 12V. I already have a 12V 1A power supply. So my questions are: Can I use the circuit below to get these three voltages? Is it ...
1
vote
1answer
52 views

Would this be ok to control the speed of a PC fan? [closed]

I have a 240mm PC fan connected to a 12v adapter. The fan is quite noisy and i would like to have the option to turn the speed up/down or off completely. The Fan is: Current (A): 0.18 The 12v Mains ...
2
votes
2answers
95 views

Can I use this high-side driver with arduino?

I have salvaged a PCB with quite few single and multi-channel high side drivers. One of the is VN5E010AH. If I understood datasheet, this chip can drive high voltage using low voltage cmos compatible ...
1
vote
0answers
44 views

Switching cold cathode fluorescent lights on and off without relay?

I have a few sets of 2-in-1 CCFLs that are designed to be powered off the 12V rail of a computer PSU. I'm planning to build a large 7-seg display using them so I'd like to be able to switch them on ...
6
votes
2answers
2k views

How to make -12V from a +12V supply?

The equipment I have needs +5V +12V and -12V supplied to it. The old PSU which provided all the voltages blew to bits. I have sourced a PSU1 +5V (30A), and PSU2 &PSU3 (two identical +12V (2A) ...
0
votes
2answers
178 views

How to supply power to a 12V solenoid from China, getting hot

I bought this solenoid from ebay and was wondering how to power it. It says 12 volts as you can also see from the picture, but I tested it with putting a 9V battery straight to its terminals for a ...
1
vote
1answer
448 views

Which diodes for 12v indicator light circuit?

Which diodes for 12v indicator light circuit? I have a car whose signal light audio indicator is too soft to hear. I would like to set-up an visual indicator on the dash for when the signal lights ...
6
votes
1answer
1k views

Replacing incandescent bulbs with LEDs, unexpected behavior

I have an over-the-stove microwave/ hood vent combo with 2 adjustable-brightness lights. The lights appear to be 12V lamps with a G4-style connector, and they burn out all the time... like every 4 or ...
0
votes
1answer
63 views

NAND gate from BJTs: interfacing +/- 12v op-amp and 5v logic: destroy BJT with excessive Vebo?

I want to switch on a relay when both a 5v logic input is high and a (LM741 used as a) comparator is around +10v, and the circuit I planned to use is below. The problem I see with the circuit is when ...
0
votes
1answer
145 views

Reduce voltage on PSU from 52V to 12V

I'm building a mining rig and is planning on using a ESP120 HP 3kW 52V power supply. I've seen someone get it down to 48V with this mod, but I wonder some one got it down to 12V? Or is it not ...
2
votes
1answer
574 views

Control of 4 pin cpu fan with 3 pin socket and …?

I have a problem with controlling my cpu fan speed since it has a 4 pin connector and the socket on my motherboard is broken (transistor connected to it has burnt). I have it connect at the moment ...
0
votes
0answers
79 views

Discharge limit on a 12V 9800mAh Lithium-ion Battery

I am running a 12V solar system that powers a 5050 LED light bar of 7.4W. Powered by a 25W mono PV and has a total 12V storage of: 1x 6800mAh 1x 9800mAh (Lithium-ion batteries in series) The ...
0
votes
2answers
119 views

12v capacitor / UPS system [duplicate]

I am looking to make a capacitor/UPS system for a few different electrical components in my car. I want to power the rear view camera, headrest monitors, and possibly the head unit for about 30 ...
0
votes
2answers
115 views

LED lights and heatsink

I want to make a light for my boat roof. If I were to buy these (or similar), would I need to mount them to a heatsink, or would they be fine just as is? The largest size one has a power output of ...
0
votes
2answers
967 views

How to connect a Inductive Proximity Sensor Switch NPN DC6-36V to PIC18F4550 5V

I have got a LJ12A3-4-Z/BX Inductive Proximity Sensor Switch NPN DC6-36V with this Specifications: Model: LJ12A3-4-Z/BX Theory: Inductive Type Sensor Wire Type: Cylindrical DC 3 Wire Type ...
0
votes
1answer
271 views

Charge at 24v and discharge at 12v for battery system

Is my thinking correct. Below is a simple diagram of the concept I want to check. Is this: 1: Possible 2: Feasible? I.E are there any concerns or foreseen issues with this design? Edit:
1
vote
2answers
151 views

How to use ordinary voltage regulator from a 40amp source?

My power source is 12v 40amp(car battery). My project needs 12v but only 500 or 1000ma max. My 12v voltage regulator (NTE960) explodes with 40amps, so I must reduce the current (too much current for ...
3
votes
2answers
309 views

12V Battery Backup Supply for GPRS Tracker

I have little knowledge on electronics apart from following a few guides. I have made a few 7 segment displays, nothing complicated. Recently my girlfriends car was stolen and she has an insurance ...
1
vote
1answer
80 views

12v socket not providing enough current for mobile phone? [closed]

I've just installed a 12v socket to my motorcycle. The socket has a sticker saying "12V - 1A", and the user manual says that "use is possible up to a power input rating of 12W". Taking that into ...
1
vote
1answer
157 views

How to use Battery Charge controller (BQ2002N)

I am working with an Arduino which I have a 12v power supply for, but also needs to be able to run off a NiMH/NiCAD battery pack when not connected, and recharge the battery pack when it is connected. ...
0
votes
1answer
260 views

Arduino 12v LED Downlights

I have managed to control an RGB LED Strip with an Arduino Uno R3 successfully. I would now like to switch and dim 12v LED Down lights. I am unsure of how to do this the Transformers I have are ...
0
votes
1answer
330 views

How to amplify 3.3v to 12v (PIR and led strip light)

First off this is very similar to what I need to do How to amplify 3.3 volts to 8-9v? I have a 12v power source PIR and 12v led strip lights, This is the specs for the PIR. I want to cut the leds ...
2
votes
1answer
214 views

Get 12v power from NiMH battery

I have an Arduino project that is powered from 12v/15A dc power source needs to switch to battery power and still get 12v (dc power may start/stop at any time) recharge the battery when dc power ...
1
vote
2answers
284 views

Cuttable 12V LED strip

I'm building a computer, and I want to add LED lighting to the case. However, here in Finland, LED strips are too expensive, and I found this: ...
0
votes
1answer
181 views

Black box on Arduino unsoldered itself due to overheating

Okay, so I was following this tutorial to control an RGB led strip with Arduino Uno R3: http://learn.adafruit.com/rgb-led-strips/usage And the LED strip wasn't lighting, so I tried plugging the other ...
4
votes
3answers
829 views

How to transform 5V to 12V?

I would like to transform 5V 500mA (from USB power) to 12V for a few dollars of parts. Is this possible with something I could build with some generic parts (not some expensive transformer, etc.)? ...
-1
votes
1answer
53 views

3 relays with a latching relay

I have looked for a product that has 3 relays, 1 NO and 2NC with one NC being latched. Does anyone know of the existence? How about how to build one? 12V DC as well.
0
votes
2answers
270 views

USB car charger with LED

This is related to Is it okay to keep a USB charger plugged into the cigar lighter? - I have a 12v charger that is connected to a phone dock with an integrated micro USB connector. The difference ...
2
votes
0answers
86 views

Is it possible to charge 3 parallel batteries without sending charge to the UPS?

I have a UPS (uninterruptible power supply) with a 220VAC input designed to be used with 12V batteries. It has a rated capacity of 400 watts and I've placed three 12V car batteries in a parallel ...
0
votes
1answer
118 views

Howto safely go from 230V to 12 Volts

I'm playing around with different kind of 12 LED light sourcing. Normally I have used one of these 12 V power adapters (with EU plug). But I have got this idea of changing a halogen lamp with a home ...
1
vote
1answer
121 views

Statically set the speed of a CPU fan

I have two types of DC 12V CPU fans, type AFC0612DE (Delta Electronics) and TA350DC (Nidec). Both types have PWM pins for speed control. I however do not have a controller. I would like to set the ...