If a doorbell transformer draws 20VA from a 120V source, what Is the current on the secondary side if it delivers 10V?

answers:
DaleE say: Your specs show a 2 amp current, but truth is, the transformer does not draw 20VA. It is a 20VA transformer, but the draw is half that, or less, typically in most homes. The draw is determined by the bell or chime set attached between the signal button and your 20VA transformer. To know the reality, we need the specs for the bell.

Mr. Uncouth say: Power required is fixed and pf is fixed.
Let (X) equal magnitude of transformer's secondary current.
Therefore;
(120V)*(.166666667A)*(pf) = (20 VA)*(pf) = (10V)*[(X)A]*(pf)]
20VA = [(10V)*(x)A]
(X) = 2
Transformer's secondary current = 2 Amps

frank lynn say: 20 VA is the apparent power and as its units implies is Volts x Amperes. So, assuming that the transformer has no losses (not true in the real world but to make this example simple), the input and output power are equal. So 20 VA at a 10Volt load = 20/10 = 2A.

Philomel say: 20 VA/10V=2A .

Lee26Caloo秦君子蘭 say: 20/10 = 2A

billrussell42 say: VA should remain constant, in an ideal world
20 VA = 10 V x current
current = 2 amps
but those transformers are notoriously inefficient, so I'd guess at 1.5 to 1.8 amps

James say: ?
