Many applications run on AC DC Adapter. The alternating current(AC) to directing current(DC) adapter that plugs into the wall to run your home printer or electric blanket may be warm to the touch. But If its excessively hot, that usually takes trouble.

An AC DC adaptor is a full-sized plastic box that plugs into a household electric outlet. A cable connected to the dc adapter carries safe low-voltage DC. A round barrel power connector at the cable's end plugs into your device.

Inside the AC adapter, a circuit called a regulator keeps the DC voltage steady. Normally, it becomes moderately warm.

If your device is working hard, it gets more power from the dc adaptor. The external adapter will get warmer. If overloaded use, it may become hot.

A problem in the switching adapter's circuits may cause it to run abnormally hot. If it becomes painfully hot to touch, grip it with a dry rag and remove it from the wall outlet.