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 Posted: Tue Jul 29, 2008 3:09 am Post subject: How to add 12v lamps to circuit? |
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http://www.stephenhobley.com/sound.jpg
I have this circuit, the standard Velleman mk103 sound to light kit. I
would like to control 2 20w 12v lamps. I>ve got some TIP142
transistors that should be OK to do the switching, I just don>t know
how to tap into the output to make it work.
I>ve been trying to tap just before the first LED but this is giving a
very limited response.
What>s the best way to do it?
Steve |
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ehsjr
Guest
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| Posted: Wed Jul 30, 2008 1:15 am Post subject: Re: How to add 12v lamps to circuit? |
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shobley@userfs.com wrote:
[quote]http://www.stephenhobley.com/sound.jpg
I have this circuit, the standard Velleman mk103 sound to light kit. I
would like to control 2 20w 12v lamps. I>ve got some TIP142
transistors that should be OK to do the switching, I just don>t know
how to tap into the output to make it work.
I>ve been trying to tap just before the first LED but this is giving a
very limited response.
What>s the best way to do it?
Steve
[/quote]
Come off the collector of T4 on the existing circuit
through 1K to an optoisolator. Use that to turn the
TIP142 on/off:
4N25 +--------------+--- +13.2
------ | |
T4---[1K]---|1 6| [4.7K] |
| | | /e
Gnd(9V)-----|2 5|---+---[470R]---| TIP142
| | \c
|3 4|---+ |
------ | |
| [Lights]
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+--------------+--- Gnd(13.2V)
Shown is a 13.2 volt supply for the lights to make up
for the voltage drop in the TIP42.
Ed |
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Kasterborus
Guest
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| Posted: Wed Jul 30, 2008 2:57 pm Post subject: Re: How to add 12v lamps to circuit? |
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| Thanks for your help - I will try this... |
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Kasterborus
Guest
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| Posted: Wed Jul 30, 2008 3:13 pm Post subject: Re: How to add 12v lamps to circuit? |
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On Jul 30, 10:57 am, Kasterborus <kasterbo...@yahoo.com> wrote:
[quote]Thanks for your help - I will try this...
[/quote]
I only have the 4n29 - which appears to be a darlington arrangement -
this should drop right in to replace the '25 - correct? |
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