How to handle a circuit switched by ground

Other Hardware General Electronics
14

With nothing powered on, use your multimeter to check continuity on each speaker unit:

  1. From Vcc to +speaker
  2. From -speaker to GND

I'm guessing that Vcc to +speaker will be a short (no resistance), and -speaker to GND will be open. It seems likely that the speaker units use a simple NPN transistor (or N-channel FET) between -speaker and GND. Putting a signal on the base of the NPN, presumably triggered by pressing a doorbell button, causes the NPN to conduct, which connects -speaker to GND. This completes the circuit and causes the speaker to speak.

When you connected all of the -speakers together, then triggering any one of the NPN transistors would have connected all of the -speakers to GND. This is what you experienced, right?

To be honest, though, I really have no idea what you are trying to accomplish?

Jim