I have a Hornby G8025W IP40 230V AC to 16V 400mA AC adaptor.
The output measures about 19.5V AC with no load.
What I don't understand is that if I measure the output resistance using a DMM or analogue multimeter, it reads an open circuit.
That suggests it cannot be a simple step-down transformer inside.
If it were just a transformer, you would expect to measure the resistance of the secondary winding i.e. a few ohms.
The output appears to be fully isolated from the mains input.
Does anyone know what's inside one of these adapters?
Could it be a transformer but with a capacitor (or two) in series with the output?
There are no screws, so I cannot open it up to find out what's inside without breaking it.
I am baffled.
The output measures about 19.5V AC with no load.
What I don't understand is that if I measure the output resistance using a DMM or analogue multimeter, it reads an open circuit.
That suggests it cannot be a simple step-down transformer inside.
If it were just a transformer, you would expect to measure the resistance of the secondary winding i.e. a few ohms.
The output appears to be fully isolated from the mains input.
Does anyone know what's inside one of these adapters?
Could it be a transformer but with a capacitor (or two) in series with the output?
There are no screws, so I cannot open it up to find out what's inside without breaking it.
I am baffled.