Questions tagged [circuit-protection]
A device, components, or safety measure designed to protect circuits from overvoltage, overcurrent, a combination of these; or the theory of same.
663
questions
0
votes
0
answers
35
views
Is it okay using IRL520n without Resistor and Diode for DIY Brushed ESC/DC Motor
In this chance, I want to know further after doing some experiments related to Logical level MOSFET (IRL520N) as a speed controller for brushed 820 DC motor for micro Arduino Quadcopter.
I had done ...
- 13
0
votes
1
answer
72
views
5V Short circuit protection circuit that lights an LED in the event of a dead short
I'm looking to implement a dead short protection circuit for a PCB so that if a dead short occurs in the circuit a LED lights up and the circuit is protected and no current flows. THe LED is to stay ...
- 137
0
votes
3
answers
48
views
Shorted Input Protection
I try to understand that Shorted Input Protection diode. I didn't understand clearly from datasheet. How can I find suitable diode for this protection circuit. What is use for? If I have a 28V 10A ...
- 15
0
votes
1
answer
47
views
Fuses before or after vital components? [closed]
Why are fuses/circuit breakers usually placed right after the power supply and before any critical components? Fuses are designed to be the first thing that melts or breaks down when there's too much ...
- 27
0
votes
1
answer
45
views
How to predict the voltage drop due to a fuse?
My device runs from a USB supply, typical 5V, current typically 20mA, never beyond 100mA.
I want to add a fuse. The JFC0402-0500FS claims rated current 0.50A (perfect for this application) and a ...
- 505
1
vote
1
answer
49
views
Does a modern voltage regulator provide reverse polarity protection and other protections?
I'm powering my circuit from 5V USB. Since USB is already regulated, I don't need a voltage regulator.
Will adding a modern regulator like L78M05C offer protection (besides regulation)? Concerns:
...
- 505
1
vote
2
answers
103
views
Safety of dual male / single female Y cords
On Amazon there are Y cords with two male plugs and a single, higher current female socket. These are advertised as providing a way to power equipment with higher current demands than a single outlet ...
- 11
0
votes
3
answers
57
views
Inrush current when turning amplifier on is causing RCBO to trip
TL;DR - when turning on an amplifier, it trips the RCBO. Might it be related to the fact I'm using a smart switch? Or the wrong type of RCBO? Or can I introduce an inrush current device? How can I ...
- 117
0
votes
0
answers
89
views
Fusible resistor blowing on flyback converter
I have a flyback converter circuit with AC input, and I have a fusible resistor on the hot line before the rectifier. When I hook up AC power to the input, the fusible resistor immediately blows. It ...
- 69
0
votes
0
answers
35
views
Protection Diodes on Bidirectional Bus With Two Voltages
I am designing a circuit that will connect to an existing device (the SNES) and communicate via a bidirectional data bus. As the circuits run at different voltages (5V TTL and 3V CMOS) and have ...
- 1
2
votes
1
answer
52
views
Battery thermal protection circuit
I'm trying to design a circuit to be used with some 12V LiFePO4 battery packs which don't have an integrated heater, so I can add thermal protection.
The circuit would sit between a 65W solar charge ...
- 319
1
vote
1
answer
38
views
Can Li-Ion BMSs be used with LiPo batteries?
I'm building a robot that's running on a 12S, 10400 MAh LiPo. Because of obvious reasons, the system requires a protection circuit. My question is, can I purchase this 13S (which I suppose works with ...
- 409
3
votes
1
answer
34
views
Why does AS3001:2008 Transportable Structures explicitly deny a separate earthing electrode?
As the title says, if a generator is providing a TNS earthing system connected to a transportable structure through a detachable connection, why does AS3001 state:
Isolation of the protective earth ...
- 55
1
vote
1
answer
32
views
TN-S Earthing parallel return paths when multiple MEN links
I have a bit-of a unique situation. I have a generator which is running a TN-S earthing system. It is powering demountable offices.
I assume that all sub circuits would have RCDs in the demountable, ...
- 55
2
votes
3
answers
138
views
How to quickly detect and switch off a shorted circuit (e.g. 30 VDC, 20 A intended, <5 ms response)
Summary
I'm designing a circuit that's meant to provide a short pulse of medium-low voltage, high-current, power from a capacitor bank to a low-resistance load, and I want to interrupt it if the ...
- 121
0
votes
1
answer
36
views
Diagnosing RCBO trip when heating elements turn off
First up let me know if this should be over on home improvement or similar, I selected here as I thought it would be a better place to ask more technical questions.
Recently our sub-board was replaced ...
- 2,405
0
votes
0
answers
42
views
TVS diode to protect 12V circuit
I have a simple 12V circuit with PIR, 555, couple of transistors and an outside 220mA LED light in a circuit powered from a 12V lead acid battery battery with long leads so am expecting LC spikes that ...
- 219
0
votes
1
answer
54
views
Need help to identify this chip
The input and output are both 3.3V so I think it may be a over voltage chip but I could not find the relevance chip.
- 1
0
votes
0
answers
77
views
Disconnect main power if sub-module failed
I am working on a power supply for a stepper motor driver which requires 48 V and 12 V to operate. The 12 V rail must present all the time if it was cut off for any reason then the 48V should also be ...
- 527
1
vote
1
answer
61
views
Do I need a diode & capacitor in this circuit?
I'm new to electronics as a hobby and have just designed a circuit (so please let me know if there's anything else in this circuit wrong) that uses an H-bridge motor driver to control 2 motors. I've ...
- 13
0
votes
1
answer
68
views
Protecting other circuits from Geiger power supply
I'm designing a Geiger counter power supply that boosts 3.3 V to 500 V.
The circuit is a basic voltage booster.
3.3 V power line is directly connected to inductor where high voltage is generated. How ...
- 1
0
votes
2
answers
79
views
How to use blade fuse in DC circuit as protection?
While trying to add a protection to my buck converter circuit I came across Blade Fuses, which are faster at breaking compared to glass cartridge from what I saw. The question is, how is such a fuse ...
- 409
0
votes
0
answers
51
views
TVS on 5V external input
I am transferring 5V ext. through a robot which is a faraday cage of sorts.
the line will be around 1.2 meters (4 feet).
will the TVS be good for this application? or should I consider a different ...
0
votes
1
answer
75
views
How to calculate the gate voltage and Vgs in this N-channel MOSFET reverse-polarity protection circuit?
The schematic below uses an N-channel instead of a P-channel to block reverse-polarity voltage from occurring. This means the gate voltage (and Vgs) must be positive. But there are two options I've ...
- 409
2
votes
2
answers
272
views
Will this NMOS MOSFET reverse-polarity protection circuit work?
Based on the helpful advice from the community, I realised the first schematic I made would not work as a protection for reverse polarity well due to a couple of flaws including the diode having to be ...
- 409
0
votes
2
answers
63
views
How to plug phase and neutral on this differential? [closed]
I have replaced an old differential with this one:
Since there's no indication how/where to plug in line and neutral, can you please help?
- 109
0
votes
0
answers
47
views
Does this circuit have a good enough ESD protection to protect I2C line or do I need a series resistor?
I want to be able to run a wire to an I2C device as far as posible for learning purposes, but I also want to know how to protect the I2C line from ESD events to exceed level 4 of IEC 61000-4-2.
I am ...
- 1
0
votes
0
answers
27
views
OZ960 Intelligent CCFL Inverter Controller - Current Protection Limit Modification
I have a SAMSUNG LCD Pc monitor and it shows for one second the logo and then the screen turns to totally black. The problem is on OZ960 Intelligent CCFL Inverter Controller. I bypassed the protection ...
- 135
1
vote
0
answers
120
views
Why does the voltage over a fuse increase even though there is no current
I noticed during several fuse tests that when the current goes to zero (it might be that the fuse was melted down) the voltage drop over the fuse rises a certain period of time and drops down steep.
...
- 11
3
votes
1
answer
142
views
Help on creating a Li-ion battery cutoff circuit
I am trying to make a PCB for a drone run off of Li-ion batteries for a project of mine. I wanted to protect the drone and cells from an Undervoltage situation and cut off the Li-ion battery from the ...
- 33
0
votes
3
answers
63
views
Using low voltage switch for high voltage application
I want to know if I can use the following switch to basically disconnect the 80V AC source.
The current through the switch should be 8mA. However, this is only for a few milliseconds.
I know this ...
- 1,855
1
vote
1
answer
91
views
A Current-limiting Design
I want to design a circuit that monitors the flow of the current. If it reaches above the threshold of 600mA or so, it would open circuit. Where should I start? Is there any available designs I can ...
- 13
2
votes
2
answers
570
views
Are there off the shelf power supply designs which can be directly embedded into a PCB?
I have a product design which requires a power supply to be embedded into it, very similar to a smart plug. I don't want to go through the hassle of redesigning an entire power supply to fit within my ...
- 127
0
votes
0
answers
84
views
How to protect an ADC input from a 100V AC voltage
I would like to know to how to protect my ADC from a 100V AC 50Hz input to the analog inputs of the ADS112C04.
This ADC is used to measure a max differential voltage across a shunt of 50mVrms at 50Hz.
...
- 1,855
0
votes
1
answer
40
views
Do camera batteries require a seperate protection circuit (lithium accu 1s)
I have a lot of old camera batteries lithium 3.7 V rechargeable accus (1s), because such handheld cameras keep dying due to lens failures (lots of sand and wind here).
I want to be able to reuse those ...
- 167
8
votes
4
answers
946
views
Should I protect against collapsing field effects of a microcontroller-driven small-signal relay coil?
I am building a simple engage/bypass switch for musical (e.g. electric guitar) effects. The signal switching will be done by a single coil (bistable) latching relay, such as the Panasonic TQ2-L-5V. ...
- 185
0
votes
3
answers
65
views
Isolated power supply for a digital isolator
I am using a small microcontroller board to communicate with other devices through a MAX3225 and several analog components.
To isolate the communication interface, I would like to use the ADuM1402.
...
- 3
3
votes
2
answers
113
views
MCU input pin protection
I want to use an MCU with some push buttons. There are long wires (6 meters) between the MCU input and the buttons. The wires are a normal pair, not twisted, not coaxial, etc. The problem is that ...
- 33
0
votes
0
answers
63
views
Need help in understanding discrete and active protection circuits
Reference
I'd appreciate if someone could break these circuits down and help me understand what portion does what.
For Fig 1
Does the capacitor placed just after the Zener diode (input side) serve as ...
- 121
0
votes
1
answer
71
views
Load dump audible issue and large output ripple issue
We have a load dump circuit in one of the boards and which is designed using MAX16129UAAGA IC. The under-voltage and over-voltage range of this IC is 3 V and 31.5 V respectively. Currently, we are ...
- 129
0
votes
1
answer
44
views
Protecting voltage regulator circuit against broken neutral
I have a simple voltage regulator. The voltage input is on the left side and the output is on the right side.
Input voltage (Vin) can be as high as 400V (rectified AC) and output voltage (Vout) is ...
- 241
2
votes
3
answers
103
views
Bulk capacitor sizing to protect H bridge during motional EMF
I'd like to drive a 30 V motor with this H bridge driver and an Arduino.
The problem is that on top of working in forward motoring and reverse motoring conditions, it will also work in forward braking ...
- 21
1
vote
1
answer
86
views
Using +24VDC to get +12VDC and -12VDC
I have the following circuit in my breadboard. My intention is to split a +24VDC into +12VDC and -12VDC. I'm using MC79M12 with this datasheet for the negative output and UA7821 with this datasheet ...
- 965
1
vote
2
answers
90
views
Maximum absolute voltage (and currents) on STM32G microcontroller
According to the data sheet, the maximum absolute voltage on a GPIO pin is -0.3 and +4V, respectively and a max of 20mA source/sink. I am trying to understand where these requirements come from and to ...
- 1,312
15
votes
2
answers
3k
views
Why is there sand or salt in this electrical circuit?
Can anyone tell me what this is and why this sand-like thing is used in an electrical circuit? I have never seen this kind of thing.
About the components: they are in an "electricity saving spike ...
- 183
0
votes
0
answers
50
views
Is there such a thing as a “corrosion break”?
More often than not, battery powered electronics will result in a battery that leaks, which if not caught, can corrode the whole circuit.
I recently bought a used piece of electronics with battery ...
- 101
0
votes
0
answers
80
views
Converting Balanced Audio to Unbalanced Audio without Damaging Sink
I want to receive a stereo balanced audio signal and feed it into the stereo microphone inputs via my motherboard's header pins.
I added about a 30 dB reduction in gain which looks good on the scope ...
- 463
0
votes
0
answers
31
views
Designing a simple UVLO in PSIM
I want to create a simple circuit in PSIM that does the same task as a UVLO (under voltage lockout) that only allows voltage to flow when the voltage is above a minimum level (e.g. 5V).
Since PSIM ...
- 31
0
votes
4
answers
125
views
How can I protect a 12 V, 5 A circuit from high current due to short circuit condition?
How can I protect a 12 V, 5 A circuit against high current due to short circuit?
I have tried resettable fuses but they do not work as expected. I have tried MF-USML300/12-2. In actual application (...
- 3
0
votes
2
answers
64
views
Should a flywheel diode be installed for SSR with AC load and DC input?
I have a solid state telay (SSR) that switches a 240 V AC appliances's input based on a 24 V DC input. The relay takes 24 V DC input and controls a 240 V AC connection.
I understand that for DC loads, ...
- 101