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Saturday, November 01, 2008

MOTM PT2399 Delay Module

via this auction

"The delay time is variable from about 33mSec to 300mSec by varying a resistance. The datasheet specs a maximum 300mSec delay at 1% distortion, but we found it could go to about 2 seconds with acceptable results.

They implemented voltage control by using an LDR (yellow LED and CDS photoresistor) for the resistive element. A true vactrol could also be used. They want the resitance to vary from as low as possible (for short delays) up to about 100K. Some experimentation will have to be done with the driving current levels for the LED."

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