The bleeper(buzzer) I am using is rated for 12 volts DC. It is a piezo electric bleeper and the frequency is created by an internal oscillator.
I am not aware with the functioning of peizo electric bleepers due to which I am not sure whether my estimate of 600 ohm minimum impedance is correct. My multimeter is not able to measure the resistance of this bleeper.
My question is, to calculate the impedance of this device, would it be safe to say that these type of devices consume at max 20mA? This would make the resistance a minimum of 600 ohms.
Have you come across small(around 1.5cm dia) bleeper that use more mA than this? Do most of them consume less mA than this?
If it is any help, I attached this bleeper to a 220uF capacitor charged at 15V and the sound lasted for about 3 seconds.