Stemedu 5PCS SFM-27 DC 3-24V Alarm Siren Electronic Piezo Active Buzzer, 95dB High Decibel Continuous Beep Speaker for Arduino,Black

These are decent low voltage buzzer, I use it at 12V.I bought another type of low voltage DC buzzers from Amazon that I use for alarm notification when certain temperature is reached. but wanted a different sound for different temperature.Would recommend this

I've used piezo crystal buzzers before on simple projects, and at low voltages they tend to be very quiet. I thought I'd give these a try to see how loud they are at lower voltages.This buzzer just needs a voltage, no control is required. This means it's simple to use, but only outputs a single tone.Firstly, at 12v, this is pretty loud. Not sure if it's 95db, but it's uncomfortable. It also does operate at 3v but noticeably quieter, yet still louder than other piezo buzzers. There is a caveat to this however. The buzzer doesn't start to operate until about 4.8v is applied (according to my benchtop power supply). Once sounding you can drop the voltage to 3v with no problems and it keeps going.As for power consumption, it's around 4ma per 3v. So ~4mah @ 3v, ~8mah @ 6v, ~17mah @ 12v (again according to my benchtop power supply).If it operated properly at 3v this would be 5*, but I have to drop a star because it won't start buzzing @ 3v.