# Questions tagged [short-circuit]

An impedance that is non-zero during normal operation becoming very low

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### Short circuit = zero voltage?

Reading this question and its answers (as well as other questions), it seems that in an idealized short-circuit with zero resistance, one concludes the voltage is zero. This seems completely wrong. ...
8k views

### What exactly fries the chip when you invert power supply?

From my own experience, burning microcontrollers is quite easy. Put the 5V at ground, GND at VCC and in an instant your chip is burned. What exactly goes on internally that causes it to stop ...
92k views

### Can a 12V battery give you a shock or not?

I am reading a book called "Make: Electronics" and, on page 9, it says: "Anyone who has dropped an adjustable wrench across the bare terminals of a car battery will tell you that short circuits can ...
34k views

### What exactly is a short circuit?

In my book there is no explanation of the phrase short circuit but at many places the author has used it. I had googled it. Some explain it as the flow of charge along a high potential difference ...
3k views

### Short circuit protection for high current wearable: fuse, polyswitch, TBU, circuit breaker, something else?

I am thinking about design elements for a rather high current, battery powered, wearable application. Maximum current of 40A at 5V, but typically around a third to a half of that. Power would come ...
28k views

### What can cause a Drain-Source short in a FET?

Background: I am using a Si7456CDP N-channel MOSFET in a switching power supply. The power supply and load are housed in a plastic enclosure. Yesterday, the power supply and load were working ...
44k views

### Voltage across short circuit

We know that current is passed through a circuit if there is a potential difference between the two terminals of the conductor. But in the case of a short circuit, we say that there is no potential ...
5k views

### Limiting the short circuit current of a power supply

I'm using a repurposed ATX power supply for my hobby projects since it's got 3.3/±5/±12 outputs, all of which are really convenient. But one thing I didn't really think about until I slipped my probes ...
25k views

### Can a device be damaged by water even if there is no power supplied?

For example, say I submerged a computer mouse entirely. Assuming that I ensured that all traces of the water were gone, would the device suffer any issues? It is my understanding currently that ...
2k views

### What happens if you drive the output of a LM78CT05 when the input is not connected

I have a Fairchild LM78M05CT (datasheet) as a 5V regulator for a µC circuit that also has an ICSP port. The actual circuit is the one in this question: Review of my first ever PCB design for a ...
2k views

### short circuit on the output of a linear voltage regulator

I am using the L78L33 on my board in TO-92 package; the weather outside is cold (it is used inside vehicles) and I have had it fail in one of six boards. It has worked for some hours then died out, ...
10k views

### Will a battery short out when the terminals are directly connected together or will internal resistance save it?

I intended to make a simple electromagnet, then I saw this video where the user is connecting wires together with no resistance at all. I was wondering why it doesn't short out and make the battery ...
1k views

### DS1822 1-Wire Sensor, Parasitic Power, and Strong Pull-Up Circuit

This question would be common to any parasitic 1-Wire devices from Maxim/Dallas Semiconductor. I have a functioning 1-Wire circuit to a DS1822. The 1-Wire protocol has been bit-banged on a 3.3v MCU (...
916 views

### Bus Contention - Output Pin driving another Output Pin

I've run into an unusual problem. I'll start off by describing my goal: I'm designing a circuit that can test for short circuits and open circuits in a wiring harness. The wiring harness does not have ...
107 views

### Why doesn't a short-circuit immediate consume all voltage?

If we assume a short circuit, with zero resistance (not even within the battery), would this 'infinite current' deplete all voltage within the battery? For example, if I "short" a 9V alkaline battery, ...
115 views

### One battery slot kills its sitting battery

My kid has a battery-operated toy, it runs on three AAA batteries, connected in serial. Once, the toy suddenly stopped working, but all batteries were good. I decided to disassemble the toy and look ...
43k views

### How to calculate the maximum current a AA battery can deliver for a short period of time?

I want to measure the maximum current a AA battery (full charged) can deliver for a short period of time (let's say one second) I have in mind to do this with a multimeter : setup multimeter to ...
4k views

### How can I troubleshoot an active short circuit?

What are some effective methods of diagnosing an active short circuit? By this I mean a short circuit that presents itself only after a PCB is powered on. tl;dr I have a design in the prototype ...
15k views

### Why isn't a transformer a short circuit?

I'm a newbie with electronic components and I never fully understood why transformers, while essentially being a short-circuit from a wire perspective, don't act like short circuits (i.e. they don't ...
19k views

### Can I burn components / short circuit by using a multimeter

It's probably not new to you, but sometimes we want to analyze a powered circuit with a multimeter. I love to do that, but I'm a little worried that I might burn some components or the whole circuit. ...
2k views

### Debugging an MCU short circuit

I have a board with an STM32F103VGT6 MCU. Yesterday, the MCU worked fine, I had just gotten semihosting working, LED blinking, played around getting a timer running and so on. I then decided to try ...
21k views

### Power supply short circuit protection

This circuit looks relatively simple to build. I'm not going to bother with the transformer since I have a dc adapter. I was wondering how would I adapt this circuit to use a lm317 instead of a 7805. ...
3k views

### Protecting Solid State Relays from Short Circuits

I have 4 SSRs on my board with a steady state current rating of 2A and a peak current rating of 9A (Relays are CPC1976). This product is meant to be a commercial one and the relays will be powering ...
3k views

### SCR Gate to negative

Is a short circuit that occurs for as long as an instance safe? In the following schematic done from here, I have a silicon controlled rectifier that is used as a latch (the circuit simulation doesn'...
3k views

### What problems can arise from temporarily shorting power supply of a small microcontroller circuit?

A friend purchased a microcontroller-controlled lighting device and in the process of testing it, shorted the VCC and GND together for a second or two. Coincidental or not, the device stopped working ...
2k views

### How do I find a short in an unpopulated 4-layer PCB?

I have a 4-layer PCB, designed in Eagle CAD 6.5. The stack-up is: Signal GND (ground) DVDD (digital power) Signal GND and DVDD are solid planes, with vias connecting them to layers 1 and 4. I have ...
3k views

### Why is there a short between my VCC and GND in this circuit?

I am doing a project where I am using a FPGA board which connects to a circuit I designed. It has a quad Comparator (LM339N), a few resistors and an LDR; two distance sensors (GP2Y0A51SK0F) are ...
6k views

### Why does grounding my switch cause the fuse to blow?

I'm working on restoring an old ATV, and I'm having a bit of trouble with the wiring. When I got the ATV it was missing the ignition switch, so I decided to replace it with this awesome looking ...
3k views

### How can I have a rising edge close a relay for a fixed time?

I have a problem that I don't know what the solution is called, but I would bet that there are many solution. Problem: I have to short-circuit two pins on a mainboard (power switch) when a rising ...
249 views

### Detecting when an illuminated AC doorbell is pushed

I have an 8VAC (can be switched to 12VAC if required) pushbutton bell which is in series with two "ding dong" chimes. The button is illuminated with an incandescent bulb, also in series. Pushing the ...
111 views

### First PCB (raspberry pi hat)… can't find short circuit

INTRO: Hi there, everyone. I'm working on a RaspberryPi hat PCB that drives 10 solenoids and takes in 5 inputs. I designed the PCB on EasyEDA and had the boards printed at JLCPCB and used their SMT ...
909 views

### Repairing/understanding this guitar amp master stage

The failure For the past few months I've been looking to repair my old-style Roland Cube 60 watt amp after it had been left out on a cold night. The point at which it failed was when I turned it on ...
128 views

### Open circuit test and short circuit test

The results I got are close to the required answer, but there is a question asking for drawing the open circuit and short circuit tests characteristics .. I tried to solve it, but Isc and Vt (in open ...
91 views

### Where to start repairing a faulty electronic board? [closed]

I am working on electronic card repair of textile machines. When a faulty electronic card arrives, I visually check it first. Is there a burned or cracked componenet next to it, if any, I am replacing ...
867 views

### Parallel of two shortcircuit

simulate this circuit – Schematic created using CircuitLab I have trouble finding value for I2 current. Would I1 go through NODE1 down and close the loop, so I2=0, or go to the left from NODE1 ...
3k views

### Maximum resistance allowing for short circuits

Consider a contrived circuit consisting of only cell and pot: (1) a cell with constant voltage V and constant amperage A, (2) variable resistor of resistance R initially set to its highest finite ...
789 views

### Short circuit protection for my voltage source

Can someone suggest me some short circuit protection schematic? I have 12V DC source (1.2A max. output current) and I will use it in some amateur electronics projects, but I would like to add some ...
2k views

### Using 220v transformer on 110v input

I've been looking for 115v primary 9v secondary 3.2va power rating PCB transformer and couldn't find any to replace the one that was fried. All I find is dual one, instead for example 4 pins it has 8 ...
278 views

### MOSFET-switching between two power supplys: how to avoid transverse current?

For a hobby project I would like to switch between two power supplys. The two power supplys are two 6s LiPo batteries. If one battery is empty i want to immediatelly switch to the other battery. (the ...
725 views

### Shorting two pins using a headphone jack

I've managed to "build" a shutter release for my Canon SLR by shorting two wires connected to the appropriate pins on the Canon connector. I am looking for ways to extend this into an intervalometer ...
2k views

### Short circuit or disconnect to bypass a compressor

I have an Altec Lansing ATP3 2.1 audio system PCB which I reverse-engineered, and I would like to bypass the JFET compressor that's on it. Its active components are a JFET and four op-amps. I will ...
1k views

### Choosing Fuses or MCB in 24VDC vehicle circuit

I am currently designing a 24VDC circuit for a small vehicle. I personally prefer using MCB's since they are simple to reset and easy to detect faults in the system, although i do find it rather hard ...
51 views

### TPIC6C595D Q0 pin is always high

Good day everybody! So I have a LED clock circuit, which I designed, powered by an atmega328p xmini, and whatever I do the first pin of the shift register which does the current sinking (TPIC6c595D) ...
70 views

### How to limit the current of a short circuit

I will be turning a relay on from my circuit by sending a signal 500ms to 1000ms long, and i am trying to protect against poor wiring or faulty relay from the user that causes a short circuit on the ...
177 views

### Why were the fuses not protecting the circuit? [closed]

I bought a Aprilia SR 50 Scooter with a "small" problem, the frontlight and the horn are not working, because the 10A fuse does blow up if the key is turned... I don't know what happened today, but I ...