question about transformator...
By surfer222
@surfer222 (1713)
Indonesia
October 18, 2011 8:25am CST
transformator is usually made of two coils. What i don't understand is, if at the first end of the transformator is not connected to anything while the other end is plugged in to the electricity in our home, why they didn't cause shorted circuit? did they eat some power while the other end is not connected to anything?
2 responses
@petersum (4522)
• United States
18 Oct 11
It will draw a little power due to Eddy currents in the core. The unconnected side has potential (voltage) but no current flow.
The powered side has resistance and inductance which limits the current, so a short circuit doesn't exist for alternating current.
@surfer222 (1713)
• Indonesia
18 Oct 11
i'm still hard to visualize what happened... if i just make one coil and there's no core, will it cause a shorted circuit?
@petersum (4522)
• United States
18 Oct 11
That depends on the resistance or inductance in the case of AC. These are determined by the wire thickness and number of turns. The thinner the wire, the more resistance per meter it has.
A single coil without a core (other than plastic or paper) can be an electromagnet, or it could be part of a radio frequency tuned circuit with a capacitor either in series or parallel.
You might want to look up "Induction Furnace" to get an idea of single coil usage.
@owlwings (43897)
• Cambridge, England
18 Oct 11
Because one coil is connected, a transformer will draw power even if the other coil is not. Due to something called 'Back EMF' the resistance will be higher and so less power will be consumed but it will still always use some.
It won't be a 'short circuit' because that always means 'little or no resistance' and the mains side of a transformer has quite a high resistance.
