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bitrex
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What is "reverse Hfe"?
Hey everyone, I'm looking over a synthesizer schematic that has a 2SC2878 transistor in shunt with the main output - I think it's connected up in some kind of power on muting circuit for protecting speakers against turn-on thumps. Interestingly, this transistor has something called "Reverse Hfe" - I assume this means for an NPN transistor it will turn on if the base-emitter junction is negatively biased as well as positively? I've looked on the web and can't seem to find a good explanation of how such a transistor would be manufactured.
The datasheet for the device is here: http://www.datasheetarchive.com/pdf-datasheets/Datasheets-38/DSA-757294.pdf
The circuit in question is: http://img9.imageshack.us/img9/9071/alphajuno.th.jpg
Any insight into how this circuit works would be appreciated - I guess it somehow keeps the 2SC2878 turned on until the positive and negative rails stabilize?
Hey everyone, I'm looking over a synthesizer schematic that has a 2SC2878 transistor in shunt with the main output - I think it's connected up in some kind of power on muting circuit for protecting speakers against turn-on thumps. Interestingly, this transistor has something called "Reverse Hfe" - I assume this means for an NPN transistor it will turn on if the base-emitter junction is negatively biased as well as positively? I've looked on the web and can't seem to find a good explanation of how such a transistor would be manufactured.
The datasheet for the device is here: http://www.datasheetarchive.com/pdf-datasheets/Datasheets-38/DSA-757294.pdf
The circuit in question is: http://img9.imageshack.us/img9/9071/alphajuno.th.jpg
Any insight into how this circuit works would be appreciated - I guess it somehow keeps the 2SC2878 turned on until the positive and negative rails stabilize?
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