Need a joke that can make people laugh.

I am an electrical engineer, and I always carry an electric pen in my pocket, which contains a battery.

One day, I accompanied my girlfriend to buy a sweater. The salesman enthusiastically introduced a model: "This sweater is of very good quality and can't afford static electricity."

I silently took out my electric pen and scratched it gently on my sweater, and immediately there was a beep.

The salesman looked black: "You don't have to be so professional to buy clothes."