A DC buzzer. When power is applied, it will make and break rapidly, transmitting a continuous noise when the switch is on, or when the key is down.
I once connected a morse code practice key with such a buzzer, and a 1.5V D cell battery, to an antenna, and it was audible on the AM broadcast band for several hundred feet. Bacon, WA3WDR ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
