[sdiy] ASM LFO - any experiences?

[harrybissell]

well OK... but I don't think that most LEDs really exceed what an opamp
can easily
supply. You probably don't want more than 10mA anyway.  OTOH a buffer
(and yes...
I didn't look :^) might possible be run from a different power supply so
that the main synth
supply is not affected (as often happens)

H^) harry

Scott Bernardi wrote:

> Remember LED's need quite a lot of current to light up properly - they
> would load down an opamp.
> Here's a circuit that uses a differential pair built of a couple
> transistors to drive the two color LED
> http://home.comcast.net/~sbernardi/elec/og2/og2_lfo.html
>
> Paul Perry wrote:
>
>> > Also, I'd like to add an LFO indicator that would increase
>> > brightness
>> > on both the positive and negeative swing. Could I used a bridge
>> > rectifer or is there an easier way?
>> >
>> An amusing approach might be to use one of those two-color leds
>> that
>> are red or green depending on which way the current flows.
>> You could just have a buffer and a resistor to the diode & the
>> other
>> end of the diode to ground.
>> Then when the lfo is + it glows red on the peak & green on the -ve.
>> paul perry Melbourne Australia
>>
>>
>>
>>