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
39 views

12v Latching on/off switch with momentary function

I'm looking to control a flashing light unit in my car that has several selectable patterns. It uses basic 12v+ to power and a basic +12v momentary to switch to the next pattern in a logical list. ...
0
votes
1answer
44 views

Can I use a 12v battery to power my 89W TV [closed]

I want to use a DC 12V battery to power my 89 watts LED TV. Is it possible and how long will it last?
0
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0answers
48 views

Control 12v 5A Pump using Arduino

I am currently developing a fluid controller using Arduino and a 12V 5A pump, whose speed can be controlled by a voltage input. From some google searches, I managed to find a circuit diagram that ...
-1
votes
1answer
61 views

can i use 12v battery while charging? [closed]

hello guys i have 70AH 12V battery and i have triple phase charger can charge from (0 to 140 ah batteries ) the chager turn off automatically when the battery full charge and i have 12V to 220 V ...
1
vote
2answers
38 views

How to use arduino and P-channel & N-channel MOSFET to control voltage to PT2264 address pins

Im looking to control a PT2264 RF transmitter module from an arduino so that I can transmit to different receivers. To do this I need to supply either +12v or 0v to the various address pins of the ...
3
votes
2answers
216 views

How can I model a relay in LTSpice IV?

I would like to use a 12V relay in my LTspice circuit, however there is no relay in the component list. How can I do? Relay model: SRD-12VDC-SL-C
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2answers
34 views

TEC 12706 not drawing more than 1.6A when powered by a 12V PC SMPS

I have recently bought TEC 12706 device from Sunrom.com; The specification says that the device can draw more than 6A current at 15.4V and internal resistance is ~2 ohms. But when I measured the ...
0
votes
0answers
60 views

Replacing parallel 12V incandescent bulbs with LED “bulbs”, voltage problems

My van has six "25W" bulbs in parallel on a 12V-nominal circuit. If I unplug all the bulbs, leaving six empty sockets, then I see pretty much the same 12.5V at the sockets as I see at my battery, and ...
1
vote
2answers
73 views

How can I detect which DC power source to send to an underwater camera housing?

I have a small problem and hoping someone can help: I am trying to design and build a reasonably universal underwater housing for some different cameras. there is a breakout box on the surface and ...
1
vote
1answer
45 views

Solenoid Valve blowing power LED - how can i protect the LED?

I have this simple circuit setup and working well to turn a solenoid valve on (close it) and off (open it again) for a watering system I use. missing is an on/off switch before the VCC. However, I ...
0
votes
0answers
66 views

What tool can monitor voltage on a bundle of wires?

I'm working on a vehicle and trying to determine which wires control which circuits - power windows, power locks, starter, trunk release, etc. I've searched but have not been able to find the wiring ...
-6
votes
1answer
54 views

running motors from ownely coupled generator [closed]

i want to do the experiment on motor generator my design is iamgoing to connect a 2 dc motors and 2 dc generators in that 1st dc motor and 1st dc generator is coupled 1st dc motor and 2nd dc motor are ...
1
vote
5answers
193 views

how to provide light for multiple 12 v led lights for 2 weeks

I'm participating in an art show soon in which I am making "sculptural light paintings" of which require a few 12v LED strips. They're the kind that work in aquariums and car's taillights and whatnot, ...
-5
votes
1answer
76 views

Using a power bank to power a router for a few seconds [closed]

Where I live, the electricity often goes out for about 15 seconds, until the backup generator kicks in. I need a cheap way to protect my wireless router and keep the connection uninterrupted for ...
0
votes
2answers
32 views

Use a li-ion battery at two different voltages

I scavenged a li-ion battery from a broken laptop. It is made of 6 Samsung ICR18650 cells (3.75V 2800mAh), parallels two by two so that the total pack is in fact the sum of 3 cells at 3.75V, so 11.25V ...
2
votes
2answers
84 views

Basic 12V Step-Start Circuit For Automotive Fans: Troubleshooting

To keep this short and sweet, I wanted to make a circuit/controller to decrease the inrush current on a large powerful fan for my race car. I ideally just wanted something that wouldn't let the amps ...
0
votes
0answers
88 views

12V / 3.3V soft power switch circuit

Based on the following circuit I would like to build an MCU-controlled latching power switch that switches 12V instead of 5V while still being controlled by 3.3V (tolerant up to 3.6V) GPIO pins of an ...
1
vote
1answer
50 views

Using 12v to supply a Raspberry Pi with a switching regulator

firstly please forgive any confused terminology, I'm not an electrical engineer by trade! I have a Raspberry Pi which is operating a series of relays via its GPIO pins. On the other side of the ...
0
votes
0answers
32 views

Help with solar panel/battery & load calculations

First solar project and I've been researching for a couple of days but still struggling with some basics. Trying to set up a simple 12v system, maintained by a solar panel. Solar Panel> Charge ...
1
vote
4answers
135 views

12V solenoid drawing more current than it needs

I'm fairly new to practical electronics so I apologize if any of this is obvious. I am currently trying to use a microcontroller to control the energizing of several 12V solenoid valves using a PC ...
0
votes
4answers
194 views

Heating a 1km long wire to 110 C using a 12v supply from a car cigarette lighter

I am a complete newbie to anything electrical/electronics. I am doing a project where I need to heat a 1 km long (Nichrome/Kanthal) wire to up to 110 degree Celcius. The only power supply available is ...
0
votes
1answer
37 views

Dual output/dual input canceling 12v trigger

I have a video projector with two 12V trigger outputs (output impedance: 4.7 kilohms). It is attached to two separate motorized screens. Unfortunately the projector software makes the second trigger ...
0
votes
1answer
31 views

Need to add blinker module to relay trigger

simulate this circuit – Schematic created using CircuitLab I have a simple light controller box. I have a 2 channel relay that controls a red and green light by magnetic switch. so we can ...
0
votes
0answers
69 views

Voltage regulator circuit - running off a 12V vehicle battery

I am designing a circuit for power regulation [rerquire 5V and 3.3V supplies] from a 12V vehicle battery. The circuit in its current form is attached. Max current drawn by the circuit in normal ...
1
vote
1answer
66 views

12V 345 Amp lawn mower battery to a 12V 10 amp motor?

I have a 12v scissor jack that is meant to plug in to a car cigarette lighter, which I believe is around 10 amps. However, I want to hook this jack directly up to a 12V battery, which is rated at ...
0
votes
3answers
96 views

Is there an affordable Power Supply capable of 12 Volts and 7 Amps? [closed]

I am trying to power a pump that requires 12 Volts and 7 Amps to run. I have looked around but cannot seem to find a power supply capable of the voltage and the current. Does anyone know where would ...
0
votes
1answer
81 views

What kind of relay do I need for for 12V source with a 5V control voltage

Trying to figure out which relay I need for a project I'm working on. The source is a 12V battery, and I'm looking to turn on a 12v solenoid using a relay. I want the control voltage on the rely to be ...
1
vote
1answer
491 views

Dropping 12V to 7.4V

I'm trying to power up my NXT Mindstorm Brick which needs 7.4V (at least, that's what the battery output is) with a 12V Power Adapter. I'm doing that because I want a constant supply from the socket ...
1
vote
0answers
107 views

Convert a NO push button into an On/Off button

I'm building a boombox, and it needs a couple of switches for main on/off, voltmeter on/off and LED lights on/off. Since I don't have any metalworking tools I am going to buy a premade front panel, ...
0
votes
1answer
68 views

Time delay relay

I am having trouble figuring out what kind of time delayed relay I need for this circuit or if anything will work even. It is used to keep a dome light on for a few seconds in a vehicle after the ...
1
vote
1answer
117 views

Why are some AC/DC adapters light while others are heavy?

I was browsing the thrift store and found a nice pair of JBL 2.0 computer speakers, but they lacked a power adapter. They call for a 12V 1A supply. I have a ton of "bricks" lying around, but no 12V ...
0
votes
2answers
294 views

Generating 12V PWM from 5V PWM

I am generating a 5V PWM signal from my MCU (an Atmel ATMEGA1284P). I need to convert this to a 12V PWM signal. For this I designed the circuit below, something very similar to a Sziklai pair, but ...
0
votes
0answers
82 views

Solar panel - voltage regulator

I am contemplating the possibility to run a trolling motor (to push my canoe) with a 250W solar panel. Electrical Specifications: Peak power: 250 W (minus 0, plus 5W Tolerance!) Optimum operating ...
0
votes
0answers
62 views

Detect a 12V signal with an Arduino [duplicate]

Using a Pro Micro Arduino I want it to look for a 12V signal and turn on a light when it is present. After a quick search I found this, and wired everything accordingly. However after writing code it ...
0
votes
1answer
164 views

Accidentally soldered in 12v 60ma bulbs in a 14v 95ma circuit - dangerous?

I was replacing some lights in my car's HVAC control box, and I used 12v 60ma bulbs (link), and after reinstalling it in the car (bulbs are working), I was doing some Googling and noticed that some ...
0
votes
1answer
67 views

Turn off device when USB power is present

I have a device I'd like to turn off when power is available via a USB socket. The device that needs to be turned on/off is powered by a 12v DC 0.5 amp adapter. USB sockets should have a max 5v 0.5 ...
2
votes
2answers
290 views

+5V and -5V power supply from 12V DC

I'm creating an RGB switcher for a car video system and would like to use the MAX466 chip, which needs -5V, GND and +5V. I have no idea how to change normal 12V DC (car battery) to dual 5V. I found ...
0
votes
1answer
158 views

Designing power supply with 5v and 3.3v from a 12v supply with switching regulators

I have 12V DC coming in from a power brick and I need to supply 5V @ 1A for USB and 3.3V @ 5A max for mSata and PCIe. I basically need to make a small atx power supply that I can integrate on my ...
0
votes
2answers
137 views

Automatic 12V plant watering system?

I'm planning to make a plant watering system . There is a beeper so it will alert us when the soil is dry.I have got a 12V DC motor . So i'll be removing this beeper and i need to add this DC ...
0
votes
1answer
99 views

Transistor shortcut

i would like to fade an led strip using pwm with a n mosfet led that is commanded by a two way switch ( relay and sw1 ) like this: simulate this circuit – Schematic created using ...
2
votes
2answers
450 views

Is this 12 volt LED circuit correct?

I found this "Plant Grow LED light" circuit on the Internet and I wanted to know if: (Please don't feel pressured to answer all my questions. You can just answer a few only if you like.) this is ...
2
votes
2answers
92 views

How to allow only 12v

I am looking to control a 12v LED light off of a zwave appliance module. Here is my issue, the zwave module outputs about a 5v pulse every few seconds while in the off state, which is enough to ...
0
votes
1answer
72 views

Rewiring a 12V charger

I have a Windows tablet with a charger which crapped out. The old charger was 12V / 1.5A - fairly standard but it had a rare tiny pin connector. Rather than buy a new charger, I decided to cannibalise ...
0
votes
3answers
150 views

Potentiometer - How?

I bought a 5m LED strip from Ebay and connected it to 12V 1.5Amps. I am a starter in engineering. What kind of potentiometer do I need to use to lower or increase the brightness? How many Ohms do I ...
1
vote
2answers
703 views

Transistors to switch 12V 2A

I need to switch some power to a device, so I was wondering, if this will work OK, or do I need to add some other stuff to protect it, or make it work correctly. I ran some simulations, on ...
0
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2answers
178 views

#2 L7809CV regulators, connected to #2 9vdc motors

I simply want to connect 2 motors as i show in the image, using a 12VDC power source and 2 #L7809CV, right now the circuit is this you can see in the image i made. The GND its the same source for ...
0
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2answers
247 views

Circuit Requirements for a 30 min continuous on off cycle

I would like to build a circuit (preferably using components from old common electronics like a VCR or whatever) that continuously cycles on/off in ~ 30 min intervals. Input voltage is from a 12v ...
0
votes
1answer
177 views

How Does Connecting a Battery in Series Affect Current Flow

Background: I am creating a circuit to run electronics and motors. The some of the electronics are 5V some are 12V and the motors are 24V. I have a small universal 12V battery for the electronics I ...
0
votes
1answer
87 views

mechanical relay output voltage doesn't change

As a followup to my previous question, where a 2222 npn transistor wasn't beefy enough to handle the load I was putting on it to activate a solenoid valve, I decided to try a mechanical relay board ...
0
votes
2answers
157 views

transistor toggles an LED, but not a solenoid valve

I'm working on a hobby project where I'm trying to drive a solenoid valve with an arduino (for some automated plant watering). The solenoid valve takes 12v, so I've rigged up some smaller batteries ...