Questions tagged [failure-mode]
12 questions
33
votes
5 answers
Why do car blinkers flash at twice the speed when a blinker light has burned out
On my 1999 Ford Escort, the brake lights double as turn signal blinkers. A left brake light burned out recently and my blinkers went much faster than normal when signaling a left turn. This is a convenient (and embarrassing) way to be alerted to a…
David Costanzo
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9
votes
2 answers
Burned motor controllers: possible root causes analysis
On a submarine robot we built, during an operation, we recently had 3 defect thruster motors (the internal power PCBs have many burnt components, 2 of the motors cracked open due to internal pressure).
Short question: what might have caused it? Do…
Sandro
- 5,519
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9
votes
3 answers
How to turn off an entire circuit when one LED fails (in the event of an open branch)?
I'm wondering how I can have a circuit to turn off in the event that one (or even multiple) LEDs fails, causing an open parallel branch. I would like all the LEDS to turn off in that case. The example circuit is attached, however, there will be 18…
ClassifiedRecon
- 101
- 3
3
votes
1 answer
Flex Cracking for 0402 MLCCs
Is there any data to show that 0402s are relatively flex crack resistant due to their size?
I can find lots of references about 0805 and larger capacitors cracking due to board flex, but I can't find any test results for 0402 caps.
Is this perhaps…
crj11
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3
votes
1 answer
Strange NTC behaviour: it goes open circuit when cooling down
My partner has a heater for heating wax that is used for waxing legs and other body parts. She told me it stopped working; it does not heat up anymore.
When I opened the device and looked at it I found that the temperature is controlled by an NTC.…
NZD
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1
vote
1 answer
What is the purpose of Failure Mode and Effect Analysis?
Our embedded controller is Advanced Drive Assist Systems(ADAS). It basically has Two software layers. Application software and low-level software.
Our controller has many low-level functions such as different communications protocols, different…
jani
- 19
- 3
1
vote
3 answers
Why is conduit for 120V building power metallic?
I saw wire conduit being installed in a building, and it was metallic. Wouldn't you want to use an insulating material instead? What if the live wire sheath started to fail? It would short to the metal conduit. Isn't that something worth…
PJazz
- 857
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1
vote
1 answer
Tools/Methodologies for failure mode effect or fault tree analysis (FMEA/FTA)
We have barely started the process towards medical device certification, and as part of that I am having a hard time wrapping my head around the appropriate way to construct a failure mode effect analysis (FMEA) document for a couple of electronic…
Edgar Brown
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0
votes
1 answer
Form C (SPDT) Relay Failure Modes and Detection
This is a question about the failure modes of an SPDT (i.e. form C) relay. Specifically, I am interested in electromechanical relays for an automotive application. I understand that either contact could be stuck open or stuck closed. But is it…
benpro
- 310
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- 9
0
votes
0 answers
Does riding the rail fatigue an opamp?
I have an LM7332 that is creating a gate voltage to drive a MOSFET. The circuit failed in the field and I'm trying to debug. One thing I've noticed is that the supply voltage to the MOSFET was sometimes low, which meant that the LM7332 had been…
Tunneller
- 101
- 1
0
votes
1 answer
Current limiter problem
I am designing the following circuit to limit current inrush to a device on startup (to about 1.5 amps over about 3 seconds). Rload is just for testing, the actual load is a bunch caps at 56v, but I have not tested with those yet. Everything…
DGB
- 51
- 5
0
votes
2 answers
Logic circuit for making sure that only one of several signals are logic-high
simulate this circuit – Schematic created using CircuitLab
I have a circuit as seen in the schematic above. It has 4 different output stages. Each one has an "Enable" pin. The user is able to freely use the mechanical switch to enable any of the…
hkBattousai
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