40 votes
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Using clothesline steel core wire rope for AC and DC

Steel, having just around 10 times higher resistivity than copper means it will take ten times the conductor area to match copper. If you measured 13 meter of it to 3.8 Ω, the cross sectional area ...
winny's user avatar
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13 votes

Using clothesline steel core wire rope for AC and DC

Agree with winny to put the inverter next to the solar panels if possible and send 230V AC (standard in Sudan) over the clothesline, despite it being more dangerous. If you need to transfer 1000W of ...
Martin McCormick's user avatar
12 votes

Would a solderless breadboard be able to handle 20V without short circuiting?

I've put 2000V on breadboards before, though with careful monitoring, current limiting, and avoiding nearby positions. Possible they might even handle as much between adjacent positions... at least ...
Tim Williams's user avatar
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10 votes
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Electronically activated circuit breaker

You already have a circuit breaker, right? They make various types of actuators for these. They're basically an electromagnet that moves a little lever that flips the breaker down. There are also ...
bobflux's user avatar
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9 votes
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Capacitor connected with a DC source

I wonder what would be the graph of current be? Well, you say it's a "pure capacitor connected with a pure DC source" hence, the current will be infinite amps for an infinitesimally short ...
Andy aka's user avatar
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8 votes

Using clothesline steel core wire rope for AC and DC

The AC side should be OK, as others have noted. As winny notes, you'll have a problem trying to carry 15 DC amps. However, I see you're using an array of 20W panels. You said 18V and 15A, so 270 ...
Andrew Veritas's user avatar
8 votes

Relay which opens very infrequently

You are referring to a 'safety relay' that actually consists of three relays - two to perform the dual-redundant output function and one to monitor the status of the output contacts. Should either of ...
vu2nan's user avatar
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8 votes

Would a solderless breadboard be able to handle 20V without short circuiting?

The safe limits will depend upon the quality of the solderless breadboard. As an example, Multicomp specifies the voltage and current limits of their solderless breadboards as 300 V and 3 A. A safe ...
user354153's user avatar
8 votes
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LTspice showing wrong voltage

A few quick points: Do use the LTspice help. If you access it using the menu, there is an option for searching and you can use "diode" or just "d" in the search, then look down ...
periblepsis's user avatar
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7 votes
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How can I manually analyse this simple BJT circuit?

You know that \$V_b=+15\:\text{V}\$. You know you have approximately \$35\:\text{V}\$ across the \$10\:\text{k}\Omega\$ emitter resistor, so the emitter current will be slightly less than \$3.5\:\text{...
periblepsis's user avatar
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7 votes
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YH11068A overvoltage

The main problem is with the feedback compensation. The design seems to have a very low cross-over frequency (between 10 and 20 Hz), resulting in very low phase margins, which causes instability. ...
DM2236's user avatar
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7 votes
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Which is the best method to measure AC voltage?

The problem The task is to detect both over-voltage and under-voltage, and to signal this condition within, let's say, 2 mains cycles, about 40ms. A strategy To detect under-voltage, the easiest "...
Simon Fitch's user avatar
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6 votes

Would 5.5 x 2.1 mm male plug work inside a 5.5 x 2.5 mm female jack for DC power?

Not all plugs are created equal. Some plugs have full, uniform tubes that have little tolerance, and a nominal 2.5mm center pin will not fit inside one designed for a 2.1mm pin. They look like this: (...
Sara's user avatar
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6 votes

Using clothesline steel core wire rope for AC and DC

I'm not an electrician, but I can help with the circuit analysis. The formula for resistance is: $$R = \rho \frac L A$$ where \$\rho\$ is the resistivity of the steel, \$L\$ is the length of the wire, ...
Adam Haun's user avatar
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6 votes

Relay which opens very infrequently

This isn't usually how you design such applications. You'd power the motor through the NO contacts of a relay which gets turned on at power up, so that each time you power up, you get a relay toggle ...
Lundin's user avatar
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6 votes

Op-Amp Selection for Dummies

The title of the AD820 datasheet says it is "rail-to-rail", but if you look more at the front page bullet points it only says that the output swings rail to rail, and the input may be used ...
The Photon's user avatar
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6 votes
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I obliterated a ceramic SMD, how to find out what piece it is?

It appears to be one of the load capacitances of the crystal which appears to be "removed": That and the one to its right have the same capacitance. Carefully remove the other capacitor to ...
Rohat Kılıç's user avatar
5 votes

Using clothesline steel core wire rope for AC and DC

Source: https://news.ycombinator.com/item?id=35730074 Credit: https://news.ycombinator.com/user?id=ltbarcly3 TLDR: connections must be protected by some kind of anti oxidation coating, if you have ...
joelparkerhenderson's user avatar
5 votes
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Why is the SCR in this circuit switching off even though current is still above th holding current?

Here is an example of what Dave is talking about in the above comment (my choices may not exactly represent your setup). Unfortunately Circuitlab does not have a simulation SCR model so I've ...
Spehro Pefhany's user avatar
5 votes

Multimeter Range and Resolution

Unfortunately, the resolution part is what confuses me. Resolution is the smallest increment that your display can indicate. In other words, if you are on the 2 mA range then the display will be like ...
Andy aka's user avatar
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5 votes

Is this signal classified as DC or AC, and what about the impedance?

but why do I sometimes see this 0 to +V signal being called AC? Depending on the context, you may call it "AC with DC offset", or "DC with AC component" (e.g. ripple). The DC ...
Rohat Kılıç's user avatar
5 votes

LTspice showing wrong voltage

There are some LED models already in LTspice, you can try some of them. They will have different forward voltages so each one will give you a different result. When I want to use an LED with a ...
GodJihyo's user avatar
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5 votes
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24 VDC system and metal ground

What you feel is static electricity that builds up on the robot body, which is insulated from earth by the wheels and tyres. It's not caused by the 24 V system so there's nothing to be gained by ...
TonyM's user avatar
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5 votes

I obliterated a ceramic SMD, how to find out what piece it is?

I am 99% sure that if you slap down the least expensive/most popular HC49/U 16MHz crystal and an appropriate size NP0 22pF capacitor it will work fine. There is nothing that requires extreme precision ...
Spehro Pefhany's user avatar
5 votes

Capacitor connected with a DC source

It is possible to get an idea of the response you requested, through the behavior of the current in an RC circuit where the resistor gradually decreases in value, approaching to zero (\$... < R3 &...
Dirceu Rodrigues Jr's user avatar
4 votes

Seeking a (simple-to-use) solution for communication over 12V DC power lines

My communication requirements are relatively slow, and I don't need a high data rate Slow data rate isn't going to actually help because... ...We always modify the BW of the data so that it doesn't ...
Andy aka's user avatar
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4 votes

How can I block low voltages (around 40 mV) but allow higher voltages?

If it's controlled by a computer, it's possible there's a small (on average) current flowing that is intended to check for filament failure. The peak voltage may be far higher than 40mV but your ...
Spehro Pefhany's user avatar
4 votes

Protecting DC power supply from accidental mains connection

The classical solution here is to put a fuse in series with your supply, which will blow when too much current is drawn. To make sure a quickly fuse-blowing current is drawn when the voltage is higher ...
Marcus Müller's user avatar
4 votes

Protecting DC power supply from accidental mains connection

I have used a circuit similar to this one. However the peak current through D2 is not well controlled and the fuse must be capable of protecting D2 by breaking the maximum fault current (out of your ...
Spehro Pefhany's user avatar
4 votes

How can I manually analyse this simple BJT circuit?

First find out if the transistor is saturated. By inspection alone, since R1 and R2 are equal, if we assume if the currents through them are approximately equal, \$I_C \approx I_E\$, the voltages ...
Simon Fitch's user avatar
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