I'm a newbie and I do not have any electronics background. I googled about it different times but I really don't understand if my calculations are right.
Here's my issue:
I have a buzzer. The technical specifications are:
Rated Voltage: 3.5V Operating Voltage: 2V to 5V Rated Current: 30mA at 3.5V Coil Resistance 17 Ohm
If I apply a 5V voltage from an arduino pin to the buzzer I should or not use a resistor?
My understanding is
- Rated voltage is 3.5V
- Rated current is 30mA then 30mA + 40mA (of the arduino PIN) = 70mA that is too high… Is that right?
- Then 5V (supplied from arduino) - 3.5V (rated voltage) = 1.5V
- According to the Ohm law R = 1.5 / 0.03 = 50 Omhs
- Since the buzzer has a coil resistor of 17 Ohms I should use a 33 Ohms resistor
Am I right?
And what does operating voltage means? Since my buzzer has an operating voltage of 2 to 5 V does that means that I can also use it without a resistor?
And what if I do not have any rated current info but I only have infos about the rated voltage and the coil resistance? is there any way to measure the rated current of a component having only these two values?