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Project_2501
Joined: Jan 31, 2018 Posts: 68 Location: Los Angeles
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Posted: Sat Jun 09, 2018 11:23 am Post subject:
How to add LED's to circuit? |
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Just curious if there is a simple way to describe adding LED's to a known circuit to indicate if there is a signal present(incoming or outgoing) in the module.
Is adding an LED rudiment as adding an LED onto an INPUT of the CV or signal[main]output of an module with an added 1n4148's or 100k resistor for protection? Would that work for these purpose? |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Sat Jun 09, 2018 7:34 pm Post subject:
Re: How to add LED's to circuit? |
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You might get away with it in some cases if you use blue or white LEDs as I have noticed those can still be quite bright and work
fine with such a large resistor value (maybe some high efficiency LEDs for other colors could work too). But usually you will need
a much smaller resistor value (somewhere between 1K..10K) and then you get in trouble with the current consumption. And because
a lot of circuits use 1K resistors on the output you could also get a very noticable voltage drop. So you will need some kind of buffer
like a transistor or opamp. It might require some experimentation to get a nice response depending on the LEDs and the voltage level.
Outputs can already have a buffer which could drive a LED directly.
duo-color LEDs are nice to indicate both positive and negative CVs btw. _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
Audio files: 23
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sun Jun 10, 2018 10:08 am Post subject:
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Be careful about things that switch fast in an audio circuit - it can cause clicks or pops in the audio. Using some kind of lowpass filter to slow the switching helps. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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cslammy
Joined: Apr 27, 2018 Posts: 206 Location: USA
Audio files: 1
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Posted: Fri Jul 19, 2019 1:50 pm Post subject:
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I recently put up a blog post with a small SMT op amp PCB I use for bi color LEDs. Not sure if that's what you're after, but it follows the same ideas already posted here--you want to buffer your signal before feeding it into the LED, and a bi color LED can give you an idea which way your current is flowing.
https://audiodiwhy.blogspot.com/2019/07/getting-started-with-smt.html
Scroll about halfway down the post. _________________ Visit my AUDIODIWHY blog and website |
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Sat Jul 20, 2019 11:07 am Post subject:
Re: How to add LED's to circuit? |
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PHOBoS wrote: | duo-color LEDs are nice to indicate both positive and negative CVs btw. |
I use those in combination with a simple comparator, green for in range and red for out of range. _________________ my synth |
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