7

You can in theory use any semiconductor junction to build nonlinear behaviour, and that's enough to implement logic, and that's enough to implement a CPU. Of course, since you might want to still be able to power them, a composition with a reliable and still low band gap is necessary. You'll find it's no coincidence that Si is the usual semiconductor, and ...


6

Your friend doesn't know enough about the subject to be talking. The transistors and other semiconductor devices on the chip carry out most of the work. Passive components (resistors, capacitors, inductors) have a part to play in the proper function of most ICs, but without the semiconductor devices (transistors, diodes, etc.) on the chip the passive parts ...


6

which semiconductors besides Si, GaAs and GaN could be used to construct logic circuits? Indium phosphide (InP) is used commercially to make very fast logic circuits. It has even higher electron mobility than GaAs, but also the same disadvantages as GaAs (expensive, lacking a native oxide) relative to silicon.


4

The circuit you have is a highly non-linear one, even if you assume that the AC voltage itself is exactly zero volts, peak to peak. Let's look at it without regard to the AC, for a moment. It'll be easier to show what I mean, then. simulate this circuit – Schematic created using CircuitLab I've removed the batteries, as they really just add "...


3

A differential amplifier generally has two transistors for symmetry, because in many applications, it is desirable for both inputs to have similar characteristics, and for them both to be referenced from the same node (e.g., ground). You can create a differential amplifier from a single transistor by applying the signals to the base and the emitter, but the ...


3

Publications like this use graphic drawing tools to make these illustrations. They don't necessarily use any kind of electronic CAD tool, so there's no checking other than human beings inspecting the illustration. In the first figure, the double-arrow appears to be... a mistake that got past the proofreader. A single arrow is enough to indicate the power ...


3

Compared to silicon, germanium requires much lower technology and is itself non-toxic. And by low-technology, I mean it is possible to make your very own germanium transistors in your garage with quite a moderate investment (both in money and learning). Then again, the "non-toxic" part of your requirements is tricky - the technology is not only the ...


3

The arrows toward a marked voltage indicate a connection (that is not shown) to a voltage rail. It is typical in modern schematics to show positive voltages at the top and negative voltages at the bottom. Very simple. In the second case, the duplicated arrows are assumed to be connected to the same voltage source since no others are shown. If there were two ...


3

This is an interesting solution, not a constant current source. An ordinary 2.7k resistor in a given input voltage range. It will be much more interesting to watch at lower supply voltages. The characteristic will have a phase with a negative dynamic resistance between 5 V and 14 V. It's a two-terminal device that exhibits an area of differential negative ...


3

I started this answer on the second question you asked on this subject, and moved it here when the other question was closed. I've tried to make it address both questions. The machines you are looking at use the bremsstrahlung effect to generate short wavelength electromagnetic waves. The X-rays and gamma rays are generated inside the field emission diode ...


2

You are discussing TWO DIFFERENT REGIONS of operation. Get an I_V plot for the bipolar device. The Saturation is at far_left, with little Vce to cause "collection" to succeed. The region where Ic ~ Ie uses substantial Vce, and "collection" of "emitter" will be nearly 100%.


2

I have helped people build science fair projects with a paper circuits, and the cool thing was that the circuit diagram and the circuit were one in the same, so everybody could understand what was going on. We used pencil lines for resistors, and it was nice to be able to adjust resistance values with just pencils and erasers. We also found that you can ...


2

A much simpler solution is to use a capacitor in series with the coil. That way you only need a single output. I use a 10uF cap for the EF2-5SNU (look up the EF2-3SNU datasheet as the 5SNU is out of production). Setting 5V on the +ve side of the cap causes current to momentarily flow through the discharged cap energizing the coil setting the relay. The ...


2

No, because the load current also flows through R2, and that happens all the time — even when VZ is not conducting.


2

Jonk has given you a good answer, but I want to point out something that may have contributed to the confusion. The signal in the example is not a voltage signal. It is a current signal. Rather than trying to imagine what happens when you apply a 5V peak to peak sigal, you should be considering what happens as the current varies. That the current source is ...


1

Your signal sources are never ideal, nor are they always floating. Connecting them in series will cause them to distort each other at best, and short each other out at worst. The transistors are there so the sources can drive their own higher impedance input so that they do not affect each other, nor are loaded down by the input as much. It also makes it so ...


1

The equivalent circuit for this schematice: will look like this: simulate this circuit – Schematic created using CircuitLab Which is equivalent with: simulate this circuit


1

But how it is possible that collector current (Ic) depends on width of base (W) but not on Vcb? Very short (and simple) answer: The collector current depends (somewhat...to a small extent) on the voltage Vcb because this voltage influences W. For a first and rough description of the transistor function this dependence is often neglected (introductory ...


1

If the input is at or near 0V then the transistors will be cut off regardless of the presence of the supply voltage Vbb. If the LED forward voltage is high relative to Vbb - 0.7V then Q1 can saturate, and at some point (maybe when Vce for Q1 falls below 100mV or so) the current will no longer be regulated. It is not possible for Q2 to saturate under normal ...


1

Q2 is approaching saturation as the collector is one diode drop above the base. The saturation region begins where the collector base diode becomes forward biased. Just what constitutes forward bias in a transistor is somewhat subjective; the junction will start conducting at quite a low voltage. If the programmed current was high enough to cause Q1 to heat ...


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