This small audio optocoupler is about the size of a pencil eraser and have a huge dynamic range, with a resistance ratio over 100,000:1. These are used extensively in audio compressors, audio level controls, audio limiters, expanders/noise gates, guitar tremolo effects, guitar amplifiers and music effect boxes. Inside the black epoxy case is a 2 lead photocell (not a photo-diode or photo-transistor) and a 2 lead LED. This is why the device finds extensive use in audio applications (photocell instead of photodiode). The LED requires about 10-16mA current and the resistance of the photocell varies from 150K up to megohms when the LED is off to under 550 ohms when the LED is on. NOTE: Dot on case marks the cathode (-) lead of the LED.
We test every vactrol that comes through to ensure there are no duds!
These are the same vactrols that we use in our 4093 Chaos NAND, MST Low Pass Filter, Vac Pak, DLY, Roboto, etc.
If you are building an LPG or Gates module, you will need a set of four vactrols tested for a certain range. Please select the LPG/Gates vactrol set.