A kind of teaching device includes a power supply, a warning LED, question LED and vibrator on each student's desk, a switch with warning function and a control switch of individual students on the table. After linking with the warning LED, and vibrator respectively, the power supply connects the warning LED switch Ka, question LED switch Kb, vibrator switch Kc and individual students control switch 7 respectively. The circuit is designed to set protecting resistance R, which is designed to link the LED and vibrator M in series or one end of transformer B. |