I have a solid state relay but I think I don't need it anymore.

  • Do you mean from the 3.3v supply pin or a GPIO? Also, what's the current drawn by the buzzer? Feb 24, 2020 at 12:39
  • I am a little bit confused. Did you use the relay to drive the buffer. And there are two types of buzzer. Piezo buzzer usually use a transistor. Electromagnet buzzers usually is directly driver by 3/5/11/24V. I sometimes directly use a GPIO pin to drive a 5/12V buzzer. I usually first use a DMM to check the current and almost find 3 to 5mA. I sometime use GPIO to drive 2N2222 or 2N7000 which in turn drives the buzzer. Active piezo buzzer are usually 5V powered, but Rpi GPIO might have a problem driving the transistor. Electromagnet buzzers can usually direct driven by Rpi GPIO.
    – tlfong01
    Feb 24, 2020 at 13:03
  • But there is a RISK of back EMF frying the GPIO pin. But the risk is very very small, because the energy stored in the coil is not big enough to fry the GPIO circuit. The back EMF spike is usually 10~15V. I know it is a bit confusing. If you wish to dig down and see the 15V spike etc, you can read the following posts. Please feel free to ask me to clarify anything: (1) raspberrypi.org/forums/…, (2) raspberrypi.org/forums/…,
    – tlfong01
    Feb 24, 2020 at 13:06
  • 1
    I have no idea what current the buzzer draws. It was just handed to me with no specifications about it. I tested it with one 1.5V AAA battery and it sounded so weak but when I used two 1.5V AAA it was loud.
    – olivakyle
    Feb 24, 2020 at 13:36


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