Re: Solving problem with when plugging in a headphone causing a shorted to ground of C77 470uF to ground and may damage U1 TDA2822

Dgyuro <dgyuro@...>

Best bet is to plug in mic and headphones & antenna before you turn on power. 

On Mar 16, 2018, at 4:37 PM, ve7hcw via Groups.Io <ve7hcw@...> wrote:

If you don't use a  speaker  with your uBITx and use only a headphone. best idea is to add a 1K resistor to the negative lead of C77 (470uF capacitor) to charge the capacitor slowly when  first power up. Now when you insert the headphone ,any accidental shorting of the sleeve and tip to ground will not create a surge  from the U1 TDA2822 since  c77 is already charged by the 1K resistor. this will prevent a loud pop on your headphone as well as possible damage to the audio amp chip.

wayne 72

Join to automatically receive all group messages.