An application field of electronics that requires high reliability and fail-safe systems. Application can vary widely in temperature ranges and a wide voltage range, typically 12v (or 24v) while off and higher when on.

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54 views

Using an automotive stereo capacitor for other uses

I am looking into using a capacitor to buffer voltage drops for a 12V solar power system. Since it seems I need a pretty big Farad number to give at least half a second of buffer time for my load, I ...
0
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0answers
26 views

Reverse Polarity & Load Dump Protection (TVS)

Based on this and other material I’ve read, I should have a diode for reverse polarity protection and a TVS for load-dump protection in an automotive circuit. I have prototyped the circuit and its ...
1
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1answer
31 views

Simple Reverse-polarity Protection for Automotive DC-DC Converter: FET or Diode?

I have recently decided to upgrade my old van by installing a few 5V/3A sockets using a 100W 12V-to-5V downstep buck that has no reverse-polarity protection. A little bit of searching here and ...
0
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0answers
19 views

Investigate methods for analog Input Overvolatge fault protection

I have 8 analog input coming from various 5v and 3.3v sensors that have to be interfaced to a 3.3v micro-controller. The main system voltage is 24v-48v , i need to protect the ADC inputs against over-...
0
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0answers
39 views

Automotive Headlight Circuit. DRL

I will begin by saying that I am in no way proficient in circuitry. What I am trying to accomplish is a circuit that runs LEDs when "Headlight (H/DRL)" has power and does not send power to "Headlight"...
1
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0answers
59 views

Start a dead battery car with a power/USB charger [migrated]

today my car couldn't start beacuse of dead battery. The battery is not old, I simply left my dash cam attached for a few days without using the car... I'm alone at home and my car is in a difficult ...
0
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0answers
37 views

How to feed audio signal to car stereo volume controller (LC75421M)?

I'm trying to hack AUX input into car stereo with tape mechanic. I managed to identify the most important circuits. The idea was to use tape mode to amplify custom audio input. The original wiring ...
-1
votes
1answer
70 views

How does wireless mobile charging work in BMW 7 series car?

I've seen a video in which the presenter just keeps the phone in some small chamber and closes it for automatic charging of smartphone.
0
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1answer
42 views

Mysterious Noise Issue in Automotive Ignition Coil Application, Arduino

I'm building a circuit to count RPM based on watching the negative pole of the primary coil in an old automotive ignition coil. I had no illusions this would be easy, but here I am stuck even though I ...
0
votes
1answer
113 views

How can CAN transceivers ouput CANH=3.5V and CANL=1.5V?

When sending a dominant bit (0bit) on the CAN bus, I understand that CAN transceivers output CANH=3.5V and CANL=1.5V. But when looking at the schematics of a CAN transceiver, I do not understand how ...
0
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1answer
51 views

Reading the closing of 12 volt circuit over RS232

Car trouble. I suspect the fuel injector circuit. I am trying to construct a com port reader that will place a timestamp into a log on the closing the 12v fuel injector circuit. The fuel injector ...
1
vote
3answers
91 views

Detecting a break in continuity where no voltage drop occurs

I have a solar charger on a vehicle which I need to protect: Schematic is down there... The charger connects to the main battery, and the solar panel, but the manual specifically states that you MUST ...
0
votes
1answer
72 views

Will my car's AM/FM antenna boost the signal of a tablet/carputer GPS?

I'm installing an Android tablet as a carputer in my '97 Hunk-o'-Junk Crapwagon, and saw a reddit post detailing a carputer install where OP linked his Jaguar's antenna to a USB GPS adapter. OP also ...
2
votes
2answers
82 views

OBD port power source [closed]

I've read on forums that OBD port can provide max 5A current at 12V. What is the source of the power? Is it coming from battery directly or is it regulated power supply from somewhere else, maybe ECU? ...
1
vote
1answer
51 views

Turn on 12v car amplifier with ATX POWER_GOOD?

Does anyone know how to turn on a 12v subwoofer amplifier, using the ATX power supply control wire for POWER_GOOD? I am using an Azza model PSAZ-1000A14S, 1000 watt, single 12v rail, computer power ...
1
vote
1answer
59 views

Practical differences between putting circuit complexity on the ground side vs the hot side

I'm wiring some computer fans behind the fridge in my camper-van to help increase ventilation. As part of this circuit, I have a temperature controlling microcontroller plus relay and a series of SPDT ...
39
votes
6answers
7k views

Why are there so many relays used in a car, instead of transistors?

Recently I did some work on my car electric circuits. I see many relays are used in car circuits. These relays are used for simple switching, and I wonder why these circuits are based on relays and ...
0
votes
1answer
81 views

Measuring vehicle's forward and lateral acceleration using a smartphone

I want to measure the acceleration (forward and lateral separately) using an android smartphone device in order to be able to analyse the driving behavior. My approach would be as follows: 1. ...
1
vote
1answer
89 views

How to reliably sample a sensor during the rotation of a wheel in a car?

I would like to sample the acceleration of the wheel axis (vertically and left-right) N times per rotation (for example once per spoke, but not necessarily). The data would be processed with Arduino. ...
0
votes
0answers
48 views

Floating Ground Adapter for Car audio line level signal?

I have a an Audi that uses the Bose external amplifier. Bose/Audi designed the system to use a single common between the head unit line out and the Bose amplifier line input, so it is four wires (FR+, ...
-1
votes
2answers
55 views

Test car phone charger amperage [closed]

I have at car usb charger. It has 2 ports and is rated 2.1A when one port is used and 1A when both ports are used. I attached samsung tablet (N8000) witch requires 2A output. So, tablet isn't ...
0
votes
3answers
192 views

Using Li-Po or LiFePo4 for diy motorcycle battery

Basically just after opinions on using LiPo or LiFePo4 for building a diy motorcycle battery. My current lead acid battery just died and i'm sick of replacing them after 1-2 years. Background info - ...
1
vote
2answers
91 views

First Time Using Integrated Circuits

I am building a circuit for a custom application. I have an old Toyota truck, and I keep leaving the headlights on, because there is no warning buzzer! I have designed a circuit that takes 3 inputs: *...
1
vote
1answer
118 views

Battery isolator reminder for classic car [closed]

I would like to add a small buzzer or led light to the dash of my old MGA which activates only when: a) the ignition is off AND b) the battery switch is on. (i.e., I have forgotten to shut off ...
0
votes
1answer
66 views

Transient Voltage Protection of an automotive circuit

Im an electronics engineer student, and im doing a project where im designing a circuit which will be used in automotive applications. More specific it contains a PIC controller which has 16 digital/...
0
votes
1answer
40 views

Run CB Radio from AUX power [closed]

Sorry if this isn't the right place for this. I have a Uniden UH015SX (https://www.uniden.com.au/resources_main/pdfs/uh015sx_OM_2yrWarranty-Updated.pdf) which requires 13.8v of DC power, but I'd ...
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0answers
45 views

voltage drop when probing a NPN transistor's emitter to collector, collector to emitter for PNP

I have some old 2SD1785 and 2SB1258, NPN and PNP transistors that I pulled off of a car audio amplifier. Using this site, I tested the transistors in question and find that they fail on the test on ...
0
votes
1answer
60 views

Switching power supplies with a relay, how to account for delay between connections? [duplicate]

this is my first post on this site (but I will have more, have no doubt), so if I have posted in the wrong section or something please forgive me. Anyway, I am currently doing a battery powered pc ...
0
votes
1answer
56 views

Wiring a car radio with two power sources

This is on a land rover I'm helping sort out for an off-road expedition I'm trying to wire up the radio with two different power sources, but what I've got at the moment is having some undesired ...
1
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1answer
67 views

Audio amplifier car board

I have a old autoradio (cassette and not AUX input ) in my car. But i don't want change because it pretty. I just want to add bluetooth. I leave fm receiver side for the true audio / radio. I want to ...
0
votes
1answer
64 views

Check my automotive solid-state power switch schematic for mistakes

I've spent a lot of time designing a simple circuit for my car. Here's what it does: it has 2 inputs, and whenever one of them is triggered, the output switch is shorted, connecting power supply to ...
0
votes
2answers
86 views

Charging a car battery with two chargers simultaneously

My car, which has a 12v silver calcium battery, is flat and I would like to get on the road as soon as possible. I got two car battery chargers that are not identical, but both can operate at 6 an 12 ...
0
votes
1answer
83 views

voltage regulation for car computer

I am looking to install a home PC computer for the car. I am concerned about voltage regulation. The car voltage can range from 10 - 14V, so would the standard PC power supply have voltage ...
0
votes
1answer
72 views

charging and discharging car battery [closed]

Apologies upfront if this is inane... I cannot find a succinct and exact answer to my question though! I have a constant water flow source in my garden - it fluctuates but with a little damming or ...
0
votes
2answers
211 views

Can I replace FP50N06 with IRFZ44N?

I own a car audio amplifier which uses a DC to DC converter having a MOSFET of the type of FP50N06. However, after prolonged use, the three of the positive rail switching MOSFET cooked and smoked. I ...
0
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3answers
111 views

Digitally Pressing a keyfob button with a microcontroller

For a project I'm working on, I need to press a car keyfob button with a microcontroller. So I soldered two wires to the circuit thing on the keyfob so I can send signals to it. This is what it ...
0
votes
1answer
39 views

Need component/device to power a light from two seperate inputs

First question here, and don't work on electronics often, so tips are welcome. This might have a very simple solution. I tried to use the schematic editor to the best of my knowledge to recreate an ...
0
votes
2answers
116 views

Boost +12v from ATX PSU to ~13.5-14.5v [closed]

I understand that what I am doing requires the utmost care and that numerous precautions should be taken in completing a project like this. Out of necessity, I am going to fashion a car battery ...
0
votes
1answer
84 views

Stabilizing the 12 volts from a car battery

I'd like to put a small gadget that I made into my car and power it from the car battery. The gadget works on 12 volts and the car provides 12 volts also. And the consumption would be somewhere around ...
0
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3answers
105 views

Car battery capacity in colder countries

The capacity of the battery is affected when the temperature drops, particularly Lead-acid batteries. So how in cold countries this situation is solved. In this PDF about automotive batteries at low ...
4
votes
2answers
259 views

Relay for Intermittent Wiper Function

I want to add an intermittent function to the wipers on my 40-year-old car without any additional switches. The details of the wipers can be found here [http://www.globalsoftware-inc.com/coolerman/...
0
votes
3answers
77 views

Automotive: how to safely connect the car's power grid to the input of an intelligent switch?

I have an intelligent switch. Let's take this one as an example - it's the one I'm plan on using, unless I find a better one. What I need to do is drive it by the voltage from the car's power grid. ...
0
votes
2answers
222 views

Bulb replacement in a car 12V 60mA vs 14V 65mA

The climate control in my car needs to have some backing lighting bulbs replaced. Can I use a 14V 65mA bulb instead of the 12V 60mA bulb that is suggested by other people who have replaced these ...
1
vote
1answer
108 views

Invert ground vs. open “signal” - relay?

first post here. I'm trying to design a circuit to invert a ground/open input signal. I.e., output is grounded when the input is open, and vice versa. I have a feeling this can be accomplished with ...
0
votes
2answers
98 views

Use of a capacitor to accomodate temporary voltage drop

I recently added a small circuit board to delay my car stereo powering up. The idea was to prevent the stereo coming on in the brief period between turning the key from ACC to START and back again. ...
0
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2answers
68 views

can someone help identify and how to test this component

I'm new to this forum and I am looking to properly identify and how to test this component. It is from a vintage Suntester power timing light Model 45XA, 6-12vDC. If anyone can help in describing ...
0
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2answers
106 views

Why Exactly Car Charger Stop When Car Is Off?

Just out of curiosity, I'm wondering why car chargers can provide no power when the car is off in most cars. Is it because the electrical system that connects to the car chargers is running off the ...
0
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1answer
100 views

Bare bones dual 12V battery isolation circuit?

I'm putting together a bare bones dual battery system for the car so I can run an inverter from the second battery while the car is off. Was thinking I could leave the starter battery as is, connect ...
4
votes
2answers
135 views

Supercapacitor with a rated voltage value greater than 2.7V feasible?

I've been researching into the development of electrical power units for Automotives (motorsports in particular, as I participate in my Uni's Formula Student team) and have started by looking into the ...
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0answers
118 views

Flashing of ECUs using UDS

Can someone please tell me if flashing ECUs is a standard procedure? Is it done the same way for all vehicles and for different ECUs? Or do manufacturers have their own methods? What exactly is ...