I would like to see if it is possible to mix two signals with one transistor: I don’t have equipment to test it but would like to know at least theoretically what could I expect: I want to mix two signals and get some kind of mixed output, it doesn’t matter how they are combined, just a random mix of the two signals.
So I though about injecting a signal into the Collector, a different signal into the Emitter and see what could come out of the Base terminal: I expect a very weak signal obviously since I am using the transistor not really as an amplifier but as some kind of mixing signal system, but the weak signal should be some kind of mix between the two signals injected into the Collector and Emitter, using the Base as an Output.
Would it work ? Could I expect to see some kind of mixing of the Signals ? Thanks for any advice or ideas…
It’s been awhile since I’ve had to deal with electronics on such a technical level, but I’ll provide you with an answer to the best of my ability.
I must say that I am having somewhat of a difficult time understanding your question though. Are you suggesting the use of a transistor as a mixer?
Regardless, I simply do not believe that this would work. You would have to ground out the base to even have the possibility of getting the signal to flow in the desired direction, which, in itself would defeat the purpose of the transistor entirely. I’m also not sure whether or not you could even get the signal to flow from collector to base, taking into consideration the material types. You do understand directional biasing, correct?
What is your profession or field of study to have you asking a question such as this?
The way a transistor works is by having a signal control the bias state of a layer between two other semiconductor layers of material.
The middle layer, the “Base”, is used to control the flow of current permitted to pass through the two outer layers and across the middle boundaries. The middle layer is of a different type of semiconductor than the outer two; PNP or NPN. Amplification (the purpose of the transistor) is achieved due to the fact that it takes extremely little current flowing into the Base in order to greatly control the amount of Collect to Emitter current (the major current) permitted to pass across the middle boundary. The Base is the control of a type of current valve between the Collector and Emitter.
What you are describing is the effort that would produce “modulation” and is exactly how it is done in analog electronics except the signals must come from the Base and either the Collector or the Emitter. The major current flows from Collector to Emitter (the standard is to think of current in terms of positive “hole flow” rather than “electron flow” and is thus opposite from that of older vacuum tubes). You choose either PNP or NPN depending on whether you want to control a negative flow from a negative voltage/current source or a positive flow.
If the major current is itself a useful signal, when another signal is placed on the base, the middle layer, the resultant flow will be a mix of the two wherein the base applied signal will be amplified as it controls the permitted flow of the major signal. The harmonics usually get distorted due to the non-linear amplification. One tries to stay on the more linear portion of the “hfe” amplification curve associated with Base current to Collector/Emitter current.
Transistors can be arranged in quite a variety of ways to achieve interesting effects. The modulating signal does not have to be the base signal and often in more sophisticated uses, it isn’t. In digital electronics, the transistor is used simply as an on-off switch by increasing its application factor, hfe, to an extreme. Any signal above a certain level opens the major flow and anything less closes it. Integrated circuits have thousands of transistors printed into their inner structure, “the chip”. Larger circuits, processors, FPLAs (Field Programmable Logic Arrays), Memories, and so on used in modern digital electronics have tens or hundreds of thousands printed into them.
because a transistor is non linear, varying the voltages independently is not sufficient to determine the output
sure it’ll work insofar as that you’ll have a voltage at the base, and that it will vary at least weakly, but good luck extrapolating meaning from whatever that voltage is… its been a few years since i’ve looked at this stuff lol
But, that is the subtle goal: the reason why I thought about it in the first place: the “destruction of meaning” or the “teasing of reality” so to say, just for fun (hence the reason why it is in philosophy forums in the first place ?).
I am not trying to solve any “problem”, I am not trying to perform any “function”, etc. I was just curious to know what happens if a signal is injected into the Collector and another in the Emitter and the base is used as an Output: I know that this is not “the way transistors are used”, I know that you can mix signals in many other ways, etc (like injecting a signal in the Emitter and a different one in the Base and getting the Output from the Collector, etc. ), etc.
I was just wondering how a transistor would behave if you made it work “upside down” in a sense, just for “fun” and “curiosity”.
I thing that you could expect a very weak signal out through the Base because of “leakage currents” and signals and such ?
It will depend on the voltages that you are feeding into the collector and emitter. That will determine whether you are in cutoff, active or saturation modes. There will be a different base current and therefore base voltage in each case. The voltages V(be) and V(ce) are critical.