CharlieHanson
  • Member for 6 years, 11 months
  • Last seen more than a week ago
  • London, UK
5 answers
10 votes
12k views
What happens if I connect a low voltage rated capacitor to a high voltage?
28 votes

A literal answer is this: There are three blown capacitors; two can be seen as spirals of grey material still reasonably in situ, the third is nothing more than the base and the internal terminals. ...

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14 answers
73 votes
30k views
My understanding of RC circuits is broken
8 votes

Forget the idea of "power getting through"; power is the product of current and voltage, and the kind of applications where you'll see this configuration of components has nothing to do with the ...

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6 answers
57 votes
223k views
What is the voltage range of a standard headphone jack from a phone?
8 votes

There is no hard-and-fast rule for headphone jacks; be it a laptop, MP3 player or a regular stereo system. I would say that a typical headphone output adheres to Line Level specifications, although ...

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3 answers
7 votes
5k views
Layout of decoupling capacitors
7 votes

If you are doing this as a hobbyist - and I don't wish to patronise in the slightest - 0402 caps are REALLY small. They require patience, steady hands, and the ability not to sneeze anywhere near your ...

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4 answers
11 votes
2k views
Gold coated multimeter test probes
6 votes

While all of the OP's questions have been answered fully, a 'real world' example is something I learnt while I was doing work experience at an Aerospace/Defence company (many years ago at the tender ...

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5 answers
4 votes
2k views
Is voltage measurement of a battery done in series?
Accepted answer
5 votes

This situation is a something of a paradox, yes, but you need to understand that 'series' does not mean 'not parallel', and vice versa. Any components which form a loop in which current is allowed to ...

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3 answers
6 votes
495 views
60Hz "click" or clipping noise when differential amplifier is surrounded by salt water
5 votes

Sound travels very well through water - try isolating the tank sonically or mechanically from whatever you can. This could be as simple as putting a dampening material (carpet!) under the tank. It is ...

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2 answers
0 votes
102 views
Electrical connection that is "AND NOT" gate
Accepted answer
4 votes

A changeover relay should do the trick, although I have made the following assumptions: C is allowed to draw power from A. You have a Neutral/non-earth return path for the coil and B. simulate this ...

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1 answers
1 votes
2k views
How to define a primitive device in Proteus?
Accepted answer
4 votes

It's in the Proteus Help file: SCHEMATIC CAPTURE HELP (F1) -> MULTI-SHEET DESIGNS -> Hierarchical Designs See the section "External Modules" - you should be able to define the child sheet as a .MOD ...

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3 answers
2 votes
4k views
Correct way to measure a wall wart voltage
3 votes

If they're transformer supplies (rather than switched mode) then yes, you're going to get higher than the stated voltage. This is likely to continue until you draw the maximum stated current, or ...

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2 answers
0 votes
472 views
Understanding an IC, MP1584, error amplifier
3 votes

How deep down the rabbit hole do you want to go? From the question I assume you don't know a great deal about control theory, otherwise the answer should have popped out at you. I'm not going to go ...

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1 answers
0 votes
112 views
What has happened to my stereo?
3 votes

It's a glue. It has got warm (no surprise) and has become conductive. My last job involved dealing with a manufacturer that used this foul stuff almost anywhere they could. Key uses, in no particular ...

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3 answers
9 votes
3k views
Why do linear voltage regulators have minimum output voltage > 0 V
3 votes

I have nothing to add for the question asked in the title, but I do have a possible solution to your second/third points of how to overcome the 1.25V barrier. As you've probably realised, the voltage ...

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2 answers
4 votes
6k views
LD1117 not providing fixed 3.3V
3 votes

That's most likely the adjustable version. This is denoted by a lack of a voltage specified on the front - the 3.3V would typically have "LD33" printed on it. This is backed up by the fact that you ...

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3 answers
2 votes
318 views
Determining the frequency response of an audio crossover (something seems off)
3 votes

I ran the circuit through Proteus simulator and the frequency sweep gave me these results: NO LOAD: 6 OHM LOAD: Both graphs run from 1k to 20k, and the key figures are as follows: fo ...

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3 answers
1 votes
712 views
What is the input voltage range for this voltage regulator?
2 votes

The absolute maximum input voltage is 15V. However, the output voltage is only specified for input voltages up to 10V; that is, if Vin is less than 10V then Vout will be between 3.168V and 3.432V, ...

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4 answers
0 votes
1k views
What is the reasons of water causing electronics or electrical appliances "broken"
2 votes

Thank you for an excuse to add more photos. The long term effects of exposure to moisture is often what kills electronics despite the product working perfectly after said exposure. Different liquids ...

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1 answers
0 votes
91 views
Help me to identify this pin
Accepted answer
2 votes

It's most likely part of Molex's KK Series. There are many alternatives made by other brands, and cheap generics, but that connector has perhaps been 'made famous' by its use as the default fan ...

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2 answers
0 votes
104 views
Help me to understand this schematic
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2 votes

With no load resistance, no current flows out of the 7812. No current flows in, either, therefore the voltage drop across R7 is almost zero. The bases of all the transistors are held at the same ...

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4 answers
1 votes
2k views
What type of motor should be used to handle a static torque (blocked shaft)?
2 votes

Torque is a function of the current drawn by the actuator (or 'motor', as I use hereon) - most motor datasheets should give this information in one form or another. In an ideal world, the ...

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1 answers
0 votes
235 views
Transistor inversions
Accepted answer
2 votes

It's not clear why you have chosen a PNP transistor to begin with - I assume it's because you had to start with something. Throw it in the bin; get some MOSFETs, Darlington transistors or beefy NPN ...

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2 answers
1 votes
2k views
Arduino PWM control MOSFET
2 votes

The trick with a computer fan is the frequency of the PWM signal - it has to be within bounds that the default Arduino PWM frequency is about 1/40th of. Intel (probably) published this datasheet on 4-...

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3 answers
1 votes
759 views
sequential leds using op amp
Accepted answer
2 votes

The answer given by @AaronD is pointing completely in the right direction, but it's leading you further than you need to go (the combinational logic), and it's not entirely telling you how to get ...

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1 answers
0 votes
9k views
Finding the Header Block in the Proteus symbol library
Accepted answer
2 votes

Eeeeeeeeeeeasy. It only took me four hours to find it originally! Within a design sheet select "2D Graphics Symbol Mode" - the icon is an 'S' in a green box, next to the line/rectangle/circle ...

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3 answers
2 votes
5k views
0805 LED on a 0805 resistor footprint?
2 votes

What is the correct size footprint for an 0805 chip resistor? Anyone? If we all fire up our favourite PCB design softwares I bet we'll all come back with a slightly difference answer. I realise I ...

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1 answers
1 votes
4k views
LM3915 VU meter not working properly
2 votes

You've saturated the input (SIG, pin 5) above the reference voltage (Rhi, pin 6). That's why the only the topmost LED flickers in dot mode and all LEDs are on in bar mode. If you look at the SF ...

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1 answers
1 votes
399 views
Which precision rectifier should I use for a 60dB LM3915 Vu-meter?
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2 votes

A full wave rectifier copes a little better for low-frequency signals than its half wave counterpart. However, what constitutes a low frequency? It depends on the input range. I shall assume this is ...

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4 answers
0 votes
2k views
Power consumed by light bulbs in series, parallel?
1 votes

Your conclusions are correct, but you might be missing a fundamental aspect of a domestic power supply: it is constant voltage, not constant current. If resistance remains constant, that means the ...

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1 answers
2 votes
2k views
Can I ignore resistor for IR LED?
Accepted answer
1 votes

Connecting two diodes in parallel: No. Don't do this. The maximum voltage for the LEDs is 3V, and only for 100us pulses. 3.3V will more than likely ruin the diode, although it's unlikely that this ...

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3 answers
4 votes
202 views
Can one tri-state pin drive two SS pins?
1 votes

It transpires that it's possible with just one PNP transistor. It preys on the larger headroom given for logic-high than logic low. R1, R3 and R4 are quite delicately balanced to leave SS2 (which is ...

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