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14 votes
Accepted

Standard Volt and Ampere

This all brings me to wonder, how much of what we use is calibrated to someone else's meter. And how many of those meters, are calibrated to yet someone else's.. and on and on. Seems like one big ...
Enric Blanco's user avatar
  • 5,801
12 votes

Can I use 1000v rectifier diodes instead of 600v rectifier diodes?

In general, it is safe to be overly conservative with a component specification. If your design calls for 600V rated diodes, then using diodes rated for 1000V shouldn't hurt anything, all else begin ...
Chris Fernandez's user avatar
10 votes

Why are high power LEDs categorized by wattage, not voltage & amperage?

Impossible to answer conclusively, but a good reason is that a lighting designer will select an "LED" (or array/cluster of LED's) that provides the illumination required, THEN design a ...
Kyle B's user avatar
  • 4,608
8 votes

Is it wattage that kills you and not specifically amps

There is more than one reason that electricity can kill you. Probably the most popular one to talk about is cardiac fibrillation. This is caused mostly by AC circuits disturbing the regular rhythms of ...
ScienceGeyser's user avatar
7 votes

What defines volts, amps, watts and mAh?

I have stopped thinking about what the electrons do and what they don't and how they figure out which way to go and how they know that the left path has less resistance and go there more - so I just ...
Arsenal's user avatar
  • 17.8k
7 votes

Can I use 1000v rectifier diodes instead of 600v rectifier diodes?

The only situation in which you would not be able to increase the voltage rating (all other performance metrics being equal) would be if the circuit depends on the reverse breakdown behaviour of the ...
Hearth's user avatar
  • 33.9k
7 votes

How long would a 48 volt battery with 40 Ah last with a 2000 watt motor?

2000W is likely the maximum the motor can draw, not what it will be drawing all the time. If you can find the part number on the motor we can tell you more. Even if you run at full throttle, it might ...
Drew's user avatar
  • 7,078
7 votes

Switch that is rated for 24 V and 4 A: can it endure 8 A if I limit the voltage?

A switch that's rated for 24V and 4A means that it is designed to have 24V across it when it is open, and 4A going through it when it is closed. Neither of these figures should be exceeded. The whole ...
TimWescott's user avatar
  • 46.6k
6 votes

Why are high power LEDs categorized by wattage, not voltage & amperage?

Yes, they are bulbs after all: you buy bulbs by wattage. The light intensity is more or less proportional to power, so that for some products you see the real wattage and the higher one "as if&...
andrea's user avatar
  • 1,599
5 votes

Powering a 1 watt LED using a 3 V coin cell

The answer to this question is just to look in the datasheet. You'll see that this cell is hopelessly wrong for what you want to do. The Panasonic CR2032 states 225 mAh capacity and typical max. load ...
TonyM's user avatar
  • 23.3k
5 votes
Accepted

What's more deadly? Watts, volts, or amps?

Arguably... ALL OF THE ABOVE. Other than being burned to death, what usually kills you with electricity is current passing through your heart. A little bit of current will not kill you but if there ...
Trevor_G's user avatar
  • 46.8k
5 votes

Getting 45.6 Ω when it should be 60 or 120 Ω on CAN bus

Our readings at the DTC connector are as follows: CAN Bus Hi pin 6 2.09 V, CAN Bus Low pin 14 2.75 V?? Shouldn't this Hi pin read the high voltage and both together equal 5 V? You probably measured ...
Rohat Kılıç's user avatar
5 votes

How long would a 48 volt battery with 40 Ah last with a 2000 watt motor?

Some rough math. At full load, we have: 48V * 40Ah = 1920Wh 1920Wh / 2000W = 0.98h So approximately one hour at full load assuming an average battery voltage of 48V and constant current (a bit over ...
hacktastical's user avatar
  • 54.4k
5 votes

Effect of two welders working on the same piece

Assuming the output circuit is similar on your welders to my Thermadyne AC/DC TIG welder it should not be a problem, assuming the workpiece is grounded. The output circuit is floating and current is ...
Spehro Pefhany's user avatar
5 votes

Effect of two welders working on the same piece

Kartman has it right. Charge flows in a closed path. The power sources are not in parallel even when welding. They do have a common negative. The voltages do not combine.
RussellH's user avatar
  • 16.1k
4 votes

Standard Volt and Ampere

Is there some sort of certification sticker one should look for when buying a meter or other equipment that indicates it is indeed tested to the actual SI values If you buy your instruments from ...
The Photon's user avatar
  • 131k
4 votes

Powering a 1 watt LED using a 3 V coin cell

This won't work. You're asking a source of power (battery) that's designed to maybe supply 60 mW to supply 1 W. End of story – you need a different power source, no circuit is able to create power (...
Marcus Müller's user avatar
4 votes
Accepted

Why are high power LEDs categorized by wattage, not voltage & amperage?

I somewhat disagree with the other answers. The power class of the diode is actually important, since low power diodes can be used with cheap FR4 PCB, higher power can be used on metal core PCBs, and ...
user1850479's user avatar
  • 17.4k
4 votes

Solar panel output volts and amperes are higher than the battery but it won't power a small DC motor

You always need a Maximum Powerpoint (MPPT) Module to get the power out of the PV-module. The problem is: if you want the maximum current out of the PV-module, then you get no voltage and no energy ...
MikroPower's user avatar
  • 1,348
3 votes

Powering a 1 watt LED using a 3 V coin cell

If you want a tiny battery with a flat shape that can deliver that kind of power (but not for long) you'll have to use a pouch LiPo.
bobflux's user avatar
  • 79k
3 votes

How to Calculate UPS Batteries DC to AC Efficiency?

A 66 Watt-hour battery generally can't supply 66 Watts for 1 hour. Probably it can do 660mW for 100 hours, and 6.6W for almost 10 hours, but after drawing 66 Watts for 39 minutes, it can't supply that ...
hobbs's user avatar
  • 7,590
3 votes

Can I use 1000v rectifier diodes instead of 600v rectifier diodes?

There is unlikely to be any negative consequences to doing this, just make sure they are big enough to handle the current. That rating is just the maximum reverse voltage they can take. More is ...
evildemonic's user avatar
  • 9,409
3 votes

Is this PSU safe for this Christmas light string

Manufacturers (ab)use convenient connectors all the time, especially for nonstandardized cases like low voltage holiday lighting strings. The fact that part A plugs into part B is not a guarantee that ...
vir's user avatar
  • 19.5k
2 votes

Standard Volt and Ampere

The label you want is "traceable to NIST" (in the USA, at least). The National Institute of Standards​ and Technology maintains primary standards, and all other standards (at calibration labs, etc.) ...
Dave Tweed's user avatar
  • 174k
2 votes

240 volts circuit amp

No, your initial estimate is right, you don’t multiply it by 2. A 2-hot leg connection has equal current in each leg to and from the load (it’s a complete circuit). You can measure consumption by ...
hacktastical's user avatar
  • 54.4k
2 votes

Why makes ground "ground"?

The bird doesn't have a voltage of 0V, its voltage is floating, which means that it has the same voltage as anything it touches. As soon as the bird touches ground, the bird gets a voltage of 0V. ...
Dampmaskin's user avatar
  • 3,797
2 votes

Is it wattage that kills you and not specifically amps

The two lowest power/current ways to kill a human are defibrillation and brain damage, and 100mA AC is roughly the amount of current that is likely to stop a heart. This amount is specced in current ...
K H's user avatar
  • 4,143
2 votes

Why are high power LEDs categorized by wattage, not voltage & amperage?

LEDs are rated by wattage because that's a clear statement of how much power they can dissipate without damage. In general, the larger the LED physical size, the more power it can handle. Larger size ...
hacktastical's user avatar
  • 54.4k
2 votes

Electrical Voltage Conversion Confusion

According to this document the adapter takes any AC voltage between 100 and 240V and either 50 or 60Hz. So you can use it directly without converter.
Unimportant's user avatar
  • 4,628

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