How to reverse a TIP31 connected to an audio jack and LED's effect?

[drabina]

Thanks. I have to order the 0.33uF capacitor as I do not have one in my parts pile. Will report back once I get it and install it.

 

[drabina]

Finally got the 0.22uF capacitor delivered and installed. The circuit works as advertised now. Just a note though: The full brightness of LEDs will be achieved when the volume is all the way up. I have changed the LEDs to super bright though and now it is all fine even at the moderate listening levels.

Thanks audioguru for all the help.

 

[FinKing]

I surfed around the internet and made this simple schematic.

Is there everything ok with my schematic?

 

[audioguru]

I answered this same question 45 minutes ago on another website.
You got it very WRONG:

 

[spec]

Update: I just noticed the date - why was this showing as a new post?

Hi, recently I've found circuits for a TIP31 connected to an audio jack to make an LED change it's brightness to the music. I'm wondering, is it possible to make the LED dim when the music gets louder, instead of getting brighter? And how would I do this?

Hi Bibbi,

Below is a circuit I knocked out for you to experiment with.

The circuit consumes 20mA (0.020A) so it will run from a battery.

You can adjust the capacitor value to change the length of time the LED is off and you can lower the input resistor value to increase the sensitivity or increase the input resistor value to decrease the sensitivity.

spec

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[JimB]

Update: I just noticed the date - why was this showing as a new post?

It was brought to the top by a multi-posting new member.
I have already deleted that post before you replied.
I will now lock the thread.

JimB

 

[JimB]

Thread unlocked so that spec can edit his schematic.
JimB

 

[JimB]

And locked up again.
JimB