How do you calculate AC load from DC load?

Answer 1

Amp measurement in a dc circuit is commonly done by use of a clamp on amp meter. The meter has a loop on one end that opens up. The loop is clamped around a wire, and the meter shows the amperage.

Answer 2

Generally, devices designed for use on an AC circuit cannot be supplied from a DC supply. The reason is that whereas DC loads are simple resistances, so current is calculated by volts divided by resistance in ohms, AC devices have their current limited by inductive and/or capacitive effects as well as resistance.

A simple example is an 24 VAC relay. Supplying this relay from 24 VDC would cause it to burn out rapidly.

Purely resistive load

An example of this is an electric fire or water heater.

Very simply, an electric element normally running on 230VAC would behave in exactly the same way if connected to 230VDC. This is not a coincidence, it is engineered!

230VAC is actually 230 VAC in RMS terms. (root mean squared). What this simply means is that the DC Equivalent Voltage is quoted, i.e. what DC level would produce the same heating effect. The actual AC voltage is 2.828 times this. You need an oscilloscope to show that this is true. Multimeters will normally show the AC RMS value.

So, to sum up, purely resistive loads will react the same way to AC and DC voltage, as long as the AC voltage is quoted as the RMS figure (this is normal).

For other loads, applying DC to an AC load will usually cause it to burn out, and applying AC to a DC load will usually result in it not working as the current is too low.

Answer 3

by using oscilloscope

Answer

One ampere of direct current does exactly the same amount of work as one ampere of alternating current. So 1 A (DC) is exactly equal to 1 A (AC). However, what you must remember is that 1 A (AC) is its effective or root-mean-square value, and it actually peaks (i.e. its amplitude) to 1.414 A if it is a sine wave.