PCF8574-transistor base switch

[tsctrl]

Hi  @xreef,

Thank you for this great library and all the effort you did.

I am having difficulties to drive a transistor using the PCF8574 GPIO as a basic switch. My objective is to turn on and off audio lines using the bjt driven by the expender.

I would like to request for sample/example schematic or circuit you use to connect a transistor to the expander.

Thank you in advance

[Renzo Mischianti]

Hi tsctrl,
here a schema with a simple npn transistor to light a led.
Bye Renzo

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[celeb10]

Hi, this works fine with an LED but I’m having trouble driving a 12V motor using the npn as a switch to complete the ground. Any idea why this would happen?

[Renzo Mischianti]

Hi Celeb10,
I think the transistor isn’t sufficient to control a 12v motor, you need more ampere, try to use a MOSFET.
Bye Renzo

[tsc7rl]

thanks Bye Renzo

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