I have an AC/DC adaptor, as it has variable voltage setting (1.5, 3.0, 4.5, 6, 7.5,9 and 12 V).
Voltage readings are larger. For 7.5V setting it provides 12V, for 12V it provides about 18V.
So I suspect this might be an unregulated power supply.
I unplugged adaptor from 240V AC power and measured the voltage across terminals. Despite a lot of time has passed I should be able to measure about 11.5 volts between positive and negative terminals.
Is it the expected behavior. If so what might be the correct way to safely discharge it ?
I use this adapter to power a DC 12V 0.60W fan. It is controlled by an IRF540 mosfet and Arduino's PWM signal.