Hi. Some laptop or mobile phone chargers still work for a couple of seconds after being unplugged. I've also seen similar behaviour with the standby lights of monitors, TVs and other devices after they are disconnected from power. Is this due to self-inductance in the transformer? If so: If self-inductance is able to maintain a substantial current for several seconds, how can those transformers operate under normal conditions where the direction of current is supposed to change 100 times per second (at 50 Hz)? Or is this just some capacitors discharging?