Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [active-components]

Components which provide a gain in the circuit where they are applied. Typical examples are transistors and op-amps.

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Differentiation between passive and active components

While I (most of the time) know from experience what components are generally considered active or passive, I have yet to come across a satisfying definition. Why do we divide electrical components into those two main categories at all? Some…
Rev
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Why is Vbe a constant 0.7 for a transistor in the active region?

I'm going to take an example of a simple common emitter amplifier. Forget about biasing and things for now, but focus on the crux of this circuit. As how I understand it, a voltage between the base node and the emitter node is varied which is…
midnightBlue
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Advantages of depletion mode FET devices over enhancement MOSFETs

I've grown the impression that JFETs and depletion mode MOSFETs are not used very much nowadays, especially in new designs. I know that they need different bias networks, especially as discrete components, so I guess there might be some advantages…
LorenzoDonati4Ukraine-OnStrike
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What is the transfer function for a first order active high-pass filter

What is the transfer function for the below circuit? simulate this circuit – Schematic created using CircuitLab Since the op-amp has unity gain, the transfer function should be the same as a passive high pass RC filter. This can be found by…
Blue7
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Active load role on this circuit and possible uses

simulate this circuit – Schematic created using CircuitLab I came with this circuit to know how an active load can improve it, I still can't finish to understand the role of active loads. The far I know is that below, Q5-Q6-R2 form a current source…
tac
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Mistake in using KVL and KCL in ideal opamp-circuit

I have the following circuit: simulate this circuit – Schematic created using CircuitLab And I used KCL and KVL to write the following sets of…
Jan Eerland
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Is MOSFET active device?

The V-I characteristics of MOSFET lies in the first and third quadrant. Therefore it should be passive device acc to me. But I have read that it is an active device. Can somebody tell what is wrong here or what am I missing? Because for passive…
Pkmb
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Why are active loads used for transistor amplifiers?

I get it that voltage drop across active loads are less compared to passive loads and at the same time they offer high small signal impedance thereby increasing gain. I cannot understand why DC voltage drop across them is lower compared to passive…
Souhardya Mondal
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Can I make active devices share voltage equally using ad hoc shunt resistors?

I have 3 active devices in series, SCRs in this case but I'm guessing that's not important. Each is rated for 2.4 kV. The total voltage I will actually apply is 6.6 kV. Leakage current is guaranteed to be 80 mA maximum, but the datasheet does not…
James Strieter
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Active load and current source purpose on NE5532

I'm trying to do some reverse engineering on the NE5532 schematic, but I can't understand how is designed the current source for the first stage. What I want to analyze now is in yellow on the picture. As I understand, the first differential…
tac
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Is a transistor truly an amplifier?

My understanding of transistor is that in it a tiny current controls a huge current. I get that concept. If that is the case, it is not amplifying anything in my opinion. Sure it does dictate when the huge current can or can't flow but it is…
user31058
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Why isn't this active rectifier circuit working?

I built the following active rectifier schematic on a breadboard, and inputted a 15 KHz 1V peak to peak sine wave from my signal generator. The output looked like a sine wave and I have no idea why. Attached is the oscilloscope picture. I ran a…
Sal M
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How can I tell if a given MOSFET can be fully driven by 5V TTL high signal? (what should I look for on the datasheet?)

How can I tell (by reading the datasheet) if a specific MOSFET can be turned fully on (with the minimum drop) with simply 5V on the gate? (assuming 5V or 12V potential between the drain and source). What specs am I looking for (preferably ones that…
64bit_twitchyliquid
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Power switch between two sources using mosfets

A new problem I have is to create an automatic switch between two sources, only one of the sources should be active at a time. There is a "backup" source (5V battery), as well as another source. Once this source drops below a 3V threshold it should…
paul23
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Is the Gate-Controlled Diode an instance of a trancitor?

I'm not sure it entirely counts. It certainly isn't useful in the way that the current-controlled voltage source is useful as the original transcitor paper describes, but more importantly, I am unsure how much its voltage output depends on current…
NXTangl
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