reversing switch

i am trying to design a small vibrating table and am looking at equiping it with an electromagnet and a switch which is capable of rapidly turning the magnet on and off to create vibration. the magnet should attract the metal table top and springs will reset it causing it to vibrate at the rate the switch is activated. is it possible to get a swich that can turn on and off about 20-30 times per second. even better if this can be varied???

Posted by greg on 27/07/2004, at 09:48 GMT