18 votes
Accepted

What is this (broken) component in the mains side of an amplifier power supply PCB?

The manufacturer logo is "Matsushita". It is one of their "V" series varistors. Looking trough their product catalogue, only the "ERZV07D431" can be a match, with marking ...
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11 votes

What is this (broken) component in the mains side of an amplifier power supply PCB?

You are looking at a varistor. It's an overvoltage protection for your circuit. https://en.wikipedia.org/wiki/Varistor To identify a replacement, you should choose one that is around 20V above your ...
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  • 121
6 votes

Total voltage of six 12V batteries in line

More or less. Actually, the battery voltage is probably more like 14.4V under charge, which results in 86V for the series string. Add in some engineering margin and it would be reasonable to make sure ...
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5 votes

Total voltage of six 12V batteries in line

Not necessarily correct, depending what "in line" means: Batteries in series or in parallel. You can connect all six 12V batteries in parallel and get a single 12V battery with 6 times the ...
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  • 5,938
5 votes

Connecting multiple Raspberry Pis to the same power

To directly answer your question, "all" you need to run four pis in parallel is a power supply that can deliver the required current (likely >12A) at 5VDC – although note that the ...
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  • 533
3 votes

What is this ringing in the inductor current?

Ringing is not unusual in dc-dc converter circuits. Every inductor has some capacitance, and every capacitor has some inductance, and pair of conductors has both. The only way to definitely avoid ...
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3 votes

Why is there continuity between the output terminal of my DC power supply and input terminal of RAMPS 1.4?

You are using the diode test option of the multimeter. In this mode the multimeter provides a current limited test voltage at the terminals and the display shows the voltage in [mV] it could reach. If ...
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  • 3,417
2 votes

STM32F038x6 Vdd and Vdda Relationship

Note that Vdda should always be > Vcc (or if lower, no more than absolute maximum 400mV) so you might need a Schottky diode to protect the chip if you have independent sources. A simpler way would ...
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1 vote

What is this ringing in the inductor current?

When the high side turns on (after the slow side turns off), the low side has been acting as a diode, and this diode has a stored charge (capacitance). Turning on the high side means it has to supply ...
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1 vote

What is this (broken) component in the mains side of an amplifier power supply PCB?

It was a varistor. Choose one rated for your voltage and similar in diameter to the blown component.
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1 vote

Two similar voltage sources equidistant from a load in opposite direction

simulate this circuit – Schematic created using CircuitLab No, this would not help. On each 200 m line the voltage will drop a bit at every small load. At the meeting point both lines have ...
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  • 3,417
1 vote

Minimum load current on boost converter

p. 15 of the data sheet mentions 'discontinuous conduction' mode. When the converter switches to this mode, portions of switching cycles are skipped (the exact method isn't clear), but the converter ...
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