82
votes
Accepted
How do I describe this circuit?
How do I describe this circuit?
Do you want subjective opinion? Or technical description?
Subjective opinion would be: this circuit is badly designed, no matter what problem the designer tried to ...
- 5,528
82
votes
Accepted
What exactly is a short circuit?
In simple and practical terms, a short circuit is an unwanted or unintentional path that current can take which bypasses the routes you actually want it to take.
This is normally a low resistance ...
- 56.3k
52
votes
Accepted
Why do we "need" resistors (I understand what they do, just not why...)?
Your understanding of how power flows through a circuit needs adjusting.
1. How much power flows through a circuit, and is taken from the battery or power source, depends on how much current flows ...
- 46.9k
47
votes
How do I describe this circuit?
The best description for this circuit is "How to NOT control a light with a switch." This was clearly not designed by anyone with even basic knowledge of electricity. Or else it was incorrectly "...
- 14.5k
45
votes
Accepted
12 V car battery short circuit with a wrench that has resistance of 0.5 ohms, how much current?
A wrench does not have a resistance of 0.5 ohms, it's way lower.
Your basic multimeter cannot measure resistances to better than an ohm or so, the resistance of leads, and the unreliability of ...
- 171k
32
votes
How do I describe this circuit?
"Battery short circuit stress tester".
This circuit will allow you to observe how the supply source reacts when short circuited. Also tests the switch under extreme fault conditions as well. An ...
- 2,651
30
votes
Diode not behaving as short circuit
Initially, the inductor resists the change of current, making the diode the path of least resistance and causing it to carry most of the current. When the magnetic field in the inductor builds up, the ...
- 1,124
30
votes
Why do we "need" resistors (I understand what they do, just not why...)?
Here's a physics-based intro to the EE concepts you're trying to understand.
Your questions are answered at the bottom.
Everything derives from the flow of "charge"
Electronics, as its root word ...
- 401
29
votes
Short circuit inside CPU during operation
Typical cause would be some electrical transient from outside coupled to an I/O pin, which causes latch-up and destruction via the power supply. Proper design of protective circuitry will generally ...
27
votes
Accepted
High short circuit failure rate of aluminum electrolytic capacitors during the production processes
That high a failure rate is unheard of for a top-quality supplier like Nichicon when properly assembled and operated conservatively. Even for no-name parts it’s not at all usual- one in 10,000 might ...
27
votes
Why did this device go bang?
The bottom of C2 is not ground. It is connected to the live input by the diodes in the bridge rectifier on every AC cycle.
During the negative half-cycle of the incoming AC waveform, the Neutral wire ...
- 33.8k
27
votes
How can I find where a short has occurred inside of a PCB?
You could connect an audio signal generator and run as much audio current as possible through the short, at something like 400 Hz or 1 kHz. Then make a pickup coil (often the iron core and coil from ...
- 931
24
votes
How can I troubleshoot an active short circuit?
It won't always work, but sometimes you can track down a short with a thermal camera... of course you have to have a thermal camera to do that.
Just power the board up and watch very closely through ...
- 241
24
votes
Oscilloscope low side connection
All these points, marked with red arrows, are connected together, physically, with metal and wires:
For example, the oscilloscope's "low-side" is the outer metalic shield on the female BNC ...
- 42.2k
24
votes
Will this short circuit to turn off an LED drain the battery?
Figure 1. Image source: RS Reed switches guide.
A reed switch is the most compact non-electronic solution to your design problem. They are available in NO (normally open) and NC (normally closed) ...
- 178k
22
votes
Accepted
If my IC is blown the decoupling capacitor is short when I test with a multimeter
It works like this:
simulate this circuit – Schematic created using CircuitLab
The over voltage damaged the IC, causing a short circuit inside it between the 5V and the ground lines (...
- 73.1k
22
votes
Accepted
Will this short circuit to turn off an LED drain the battery?
With the lid closed, the battery will be dead within minutes.
Consider using a microswitch such as this one, found on ebay
Position the lever to be depressed when the lid is closed. When the lid ...
- 42.2k
21
votes
What exactly is a short circuit?
This is a Short Circuit:
Okay, that's what I really wanted to put down. Let's see if we can answer your question with the rest of the space.
A short circuit is a connection between two elements ...
- 2,956
21
votes
Accepted
Why doesn't this capacitor short this circuit?
The capacitor is in fact a short circuit, however only temporarily.
When you first turn on the power supply, the capacitor will act like a short circuit during this initial transient phase. There ...
- 68.7k
20
votes
Accepted
Why is there a short between my VCC and GND in this circuit?
You have fallen into a classic XY problem1 trap. However, thanks for briefly mentioning the original issue, as that makes the overall situation easier to understand.
You have a genuine problem ("X"):
...
- 18.3k
20
votes
Accepted
What is the use of this diode in the circuit?
This circuit is for a buck converter. If you look into the working of the buck converter, this diode is essential for the purpose of voltage conversion.
What happens is that, during Toff duration, ...
- 476
20
votes
Accepted
Is it possible for an IC to become shorted internally?
Yes, they can.
CMOS ICs if not properly designed are particularly susceptible to latch-up conditions whereby the intrinsic body diode in one or more of the FETs starts to act effectively like a ...
- 68.7k
18
votes
How do I describe this circuit?
Current tends to select line with lower resistance. Short circuit resistance is 0 and open circuit resistance is unlimited. The current of lamp when switch is closed = zero then you have no light but ...
- 598
18
votes
5V LDO blowing up only when testing current draw
I think people are distracted by the PMOS, but the real reason is a voltage spike when the 24V is connected, due to inductance of the wiring that is even higher when the multimeter is connected, ...
- 2,705
17
votes
Accepted
Please help me debug my circuit
You have diode D2 installed backwards:
The blue/green arrow points to the banded end of the diode as marked on the PCB. The red arrow points to the banded end of the diode as you have installed it.
...
- 73.1k
17
votes
Laptop motherboard not working, quiet clicking noise
Repair tech here! Solid analysis. I advise against injecting 18V, because your main power bus of the board is probably 12V or so, and there is a chance that the switching MOSFET that converts it to ...
- 3,623
17
votes
Why is a capacitor considered a short circuit at start up?
You are mixing up two very different concepts.
When you talk about impedance you are implicitly examining the behavior of the system in an AC steady state condition, i.e. when excited by a sinusoidal ...
16
votes
Accepted
Why do engineers usually short ground and negative ports on a DC power supply?
Briefly: Earth is not automatically a reference voltage, but it's good to connect your reference voltage to earth.
Long version:
Most electronic devices today are designed such that their local ...
- 7,581
Only top scored, non community-wiki answers of a minimum length are eligible