Kevin Weddle Posted December 7, 2004 Report Share Posted December 7, 2004 I have an idea to develop a backwards transistor. I had this idea from the limitations I was getting. I wanted to operate the collector of a common base as an emitter. The reason is for the high impedance aspect of the collector as seen by the rest of the circuit. If I used an emitter, the impedance is the base resistor divided by beta. We all know that the biased base resistors must not be too high else you won't have enough current difference that is applied to the base. We all know that the impedance of this backwards transistor will be the change in voltage divided by the change in current. If I make the change in current low I have a low change in current on the output. This makes the input impedance high and the most notable feature is that I can get voltage gain. This sounds like a common emitter function, but consider that this function will produce inversion. With a backwards transitor, though you can have voltage gain, a high input impedance, and no inversion. I don't want inversion because I want a fairly large signal and the beta would change too much. I need an increase to occur on both sides of the transistor. Quote Link to comment Share on other sites More sharing options...
Guest Yevgenip Posted December 8, 2004 Report Share Posted December 8, 2004 I think it is called a MOSFET :P but I'm not sure. Quote Link to comment Share on other sites More sharing options...
Kevin Weddle Posted December 10, 2004 Author Report Share Posted December 10, 2004 Doesn't a MOSFET also have the same problem when you apply a signal to the source. The input impedance is too low. It is only 1/gm. Quote Link to comment Share on other sites More sharing options...
surajbarkale Posted December 30, 2004 Report Share Posted December 30, 2004 The common base configuration works because collector can provide same current as emitter without caring for the load voltage. Indeed collector acts as a constant current source. You can not operate emitter this way so at the max you will get an attenuator.In fact you can view a voltage regulator as the backwards transistor. And i don't think it offers any gain ;D Quote Link to comment Share on other sites More sharing options...
MP Posted December 31, 2004 Report Share Posted December 31, 2004 Kevin, do you mean a transistor that is flat on the wrong side? This would surely be put in the board backwards.(I am only joking with you) ;DMP Quote Link to comment Share on other sites More sharing options...
Guest Yevgenip Posted December 31, 2004 Report Share Posted December 31, 2004 Yeah, or a transistor with his pins misplaced, so you need to guess which pin is which! Won't that be fun? ;D Quote Link to comment Share on other sites More sharing options...
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