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.

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1answer
52 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 ...
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votes
1answer
35 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 ...
-1
votes
1answer
50 views

12v car to mains 12v [closed]

Hi I want to power my van with a x box transformer how can I do this? Can I leave the battery connected to the neg. And wire the neg from transformer to the body and pos to a switch swapping from the ...
0
votes
1answer
98 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
1answer
42 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
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2answers
69 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
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2answers
75 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 ...
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votes
1answer
58 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
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1answer
63 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
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3answers
134 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
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1answer
76 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
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4answers
299 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
133 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 ...
1
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3answers
270 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
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1answer
49 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
80 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
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0answers
36 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
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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
146 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
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1answer
265 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
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1answer
51 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
135 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
309 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
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0answers
68 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
90 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
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2answers
104 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
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2answers
634 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
195 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:
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2answers
130 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 ...
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2answers
241 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
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1answer
65 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
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1answer
112 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
238 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
298 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
196 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
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2answers
250 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
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1answer
162 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
607 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.)? ...
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votes
1answer
50 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
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2answers
204 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
82 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
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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
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1answer
116 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 ...
0
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1answer
3k views

hard-wire 4-port usb hub to my car's 12v switched cig outlet

I would like to hard-wire a 4-port usb hub to my cig outlet. I currently have the hub connected to my power inverter and have to flip a switch to turn on the power. My goal is to do a complete ...
0
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1answer
213 views

2 3.2v LED in series on 12v source

hi i am planning to install two small white light LED on my car as parking lights. so basically i am using the reflector along woth LEDs from a torch that uses 3 AA cells(4.5v), the power of LED in ...
3
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3answers
4k views

Using a 12V battery while simultaneously charging via solar panel

I have a couple of 12v batteries that I'd like to use to power a cooling apparatus while camping for several days. I also have a 15W solar panel I'd like to use to top-off the battery. Can I use the ...
0
votes
1answer
533 views

using relay to switch between video outputs

Hey all I have a simple question... would I be able to send a video signal (composite) to each relay per camera? Reason being is that I only have one video input but need to be able to use 2 cameras ...
2
votes
2answers
161 views

What do I need to look out for when converting 9V example schematics to 12V?

What do I need to look out for when converting 9V example schematics to 12V? Most of my ICs work until 18V, and it seems to me all the resistor divider stuff is based on ratios, so it should scale ...
2
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2answers
2k views

Making 12V DC from 6V AC

I've got a 1980 Honda XL 185s that has a 6 volt electrical system. The headlight uses a 6V AC, 30 watt bulb powered from the generator. The other lights (tail, blinkers) operate off of the 6 volt ...