piezo siren input ?

I picked up some piezo sirens (2) for next to nothing the other day. The guy said they are the kind people use for their car alarms. I took them home and connected them to 12Vdc and I got a tiny quick chirp everytime I reversed the polarity of the 12volts between the two leads coming off the siren. I only get a single chirp if I connect the 12V and leave it connected. This makes me think that these piezo sirens need some sort of pulsed voltage to make them wail properly. My question is 1) is the typical 12V output from an alarm brain constant or pulsed? and 2) what kind of input do the piezo siren you guys are familar with require? btw- I do have a 'typical' alarm, viper 600 something or another (USP?) Brad

Most alarms have a constant output for the siren.  All of the piezo sirens that I have installed before only require a 12V and ground to sound.  Should wire directly into siren output of alarm.

piezo electric sirens need a driver circuitry that causes the resonation. If you are talking about just the piezo electric element, with some know-how you may be able to build one if you like. Most alarm sirens already have all the circuitry in the siren so just give it power and its good.

If you already have a siren hooked up, and now you're hooking up a piezo in the interior, don't you need to use a relay? I didn't think you could just tap into the siren wire for power? Just curious because I'll be doing this soon.Q: What's the best nation in the world?

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