I would like to understand how the center tap terminal work in miniature speakers. I can see in the datasheet that a positive going voltage relative to this center tap can lower the output volume but it does not specify by how much?

How can I calculate that? How is the actual connection between the 3 pads?

Maybe it is just a parallel connection between the positive pad - the center tap terminal and half the speaker resistance. I just want to be sure of this.

Thanks for your help.

  • 1
    \$\begingroup\$ knowles.com/eng/content/download/4788/66554/version/2/file/… \$\endgroup\$ – the_moon Jul 20 '16 at 18:40
  • 1
    \$\begingroup\$ Without the manufacturer telling you, I think the only way is to measure the coil inductance or resistance at the two points? I'm guessing a center tap would likely be centered, so everything would be halved? Just an educated guess. \$\endgroup\$ – Passerby Jul 20 '16 at 19:59
  • \$\begingroup\$ Why is it for? To modify the impedance of the speaker? \$\endgroup\$ – the_moon Jul 20 '16 at 21:08
  • 1
    \$\begingroup\$ I'm guessing yes. Half the coil, half the power? Like using a center tap on a transformer leading to a smaller voltage or current. \$\endgroup\$ – Passerby Jul 20 '16 at 21:10

"a positive going voltage relative to this center tap can lower the output volume".

The datasheet doesn't actually say that. It says that "a positive going voltage... will cause a decrease in pressure at the sound outlet". I think that all it is saying is that when you apply a positive voltage as specified the internal diaphragm / speaker effectively moves inward causing a reduction in pressure at the sound outlet. You need to drive this unit with an audio signal exactly as you would a speaker.

  • \$\begingroup\$ So, I do not get why is the center tap terminal for. What would cause a decrease in pressure at the sound outlet? \$\endgroup\$ – the_moon Jul 20 '16 at 21:06
  • \$\begingroup\$ Op knows they connect an audio signal, but if they use the center tap instead of the two outside taps, how much would it be reduced by. \$\endgroup\$ – Passerby Jul 20 '16 at 21:08
  • \$\begingroup\$ @Passerby I was trying to correct the OP's confusion between output volume and pressure at the sound outlet. \$\endgroup\$ – Steve G Jul 20 '16 at 21:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.