For most consumer electronics, there'll be a transformer within the adaptor that converts AC to DC. For the basic of the transformer, I'll just assume it's just a primary coil running the secondary coil.So, the primary coil keeps on running at full power, as long as electricity is needed for the appliances. Does this mean that even on standby mode, the adaptor still takes in full power from the power socket?
the adapter contains a Transformer to drop the voltage and a rectification circuit to convert from AC to DC to smooth the rectified voltage. the transformer has only a small amount of power consumption when the secondary coil has no load, Although the winding resistance of the primary coil is a constant the current flow through it is restricted by the magnetic field. the rectification/smoothing circuit is likely to cause some load even if there is nothing connected to the outlet of the transformer.
Nobody has this exactly right, so here is what is happening: The transformer, with no load on the secondary presents a reactive impedance to the AC line which is fairly high. This is due to the inductance of the transformer. Any current flowing creates a magnetic field which induces a reverse voltage in the primary winding which in effect bucks the applied line voltage and limits current flow. Some energy is stored temporarily in the magnetic field during the positive half cycle of the applied line voltage, and then returned when the applied voltages reverses sign during the second half cycle. The net power consumption is fairly low, and is due to the resistance of the copper wire and magnetic hysteresis losses in the transformer's iron core. All of the above applies when there is no load on the secondary. When a load is applied to the secondary, the current flowing in the secondary circuit (which is also flowing in the secondary windings) creates a magnetic field which is in opposition to that produced by the primary winding. This decreases the EMF opposing current flow in the primary, so more current flows in the primary. Thus an applied load on the secondary presents a reflected load in the primary. Remove the secondary load and the reflected load disappears. So an unloaded transformer does not consume max power - but does consume a little power due to the copper and iron losses in the transformer.
primary coil keeps on running at full power incorrect. wrong. The secondary has a load, and that load draws current, which may be anywhere from zero up to the maximum load rating of the transformer, say 10 amps. Depending on the turns ratio (say it is 10:1), that amount of current is supplied by the primary, multiplied by or divided by the turns ratio. In our example, this would be 1/10 th the secondary. So if the secondary drew 10 amps, the primary would draw 1 amp from the wall socket. If the secondary drew 1 amp, the primary would draw 0.1 amp. And 0 amps would cause the primary to draw 0 amps from the wall socket (for an ideal transformer. Real world, there is a small current being drawn, how small depends on how good a transfomer it is) edit, for your additional details. I determined that it keeps on running at full blast based on the idea that it's a separate circuit. wrong Since it is always creating magnetic field (which it must, since it's a coil), and creating even when no ones taps on it, it must run at full blast at all times. wrong, with no load, the magnetic field is much weaker. Unless there's a way the primary circuit automatically knows nobody is tapping on it, it must be constantly making magnetic field at full blast. wrong.
You are right. The value of a coil is measured in Henries and is determined by number of turns, size of wire, type of wire (commonly copper or aluminum). That is the reason you should not leave adapters and chargers plugged in. When not in use they should always be un plugged from power source.
