Questions tagged [saturation]

Saturation applies to two things in electronics; core saturation in a transformer or inductor, AND transistor saturation in a BJT or a MOSFET.

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ADS1113 ADC saturation at 0 Volts while sampling bipolar signal

I'm using a ADS1113 delta-sigma 16-bit ADC to sample a bipolar signal from a force sensor at 50Hz, and I have found a weird phenomenon. When the signal negative or positive, there is no issue, but ...
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What do I add across the opamp to get a full sine wave?

I'm struggling to figure out a solution to avoid saturation, I believe the solution will require some component to be attached across the opamp to produce the same voltage out as voltage in (voltage ...
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Finding DC saturation behavior of clamp ferrites

While some chip ferrite datasheets specify maximum current and DC saturation behavior, it seems like many clamp ferrites omit both maximum current specification (which arguably is less critical) but ...
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Cascode: Which device goes into triode region first?

In the above cascode network, which device goes into triode region first, if the supply gradually decreases? Framing the question other way round, if the supply gradually increases from 0V, which ...
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LF411 behavior at -15V

I'm doing the following exercise from the Hayes' "Learning the Art of Electronics" The circuit behaves as following: When the pot's output is positive, the opamp's output is saturated at ...
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Will the current needed for core saturation (transformer) increase with applied voltage?

I was going through one of the research papers based on self-excited push-pull converters. The line below is taken from the paper: the current needed for core saturation rapidly increases with ...
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What is the fool-proof method to confirm whether the op-amp has -ve feedback?

As the theory goes, following are the 2 cases of op-amp operation: If there is a valid -ve feedback, inverting terminal volt = non inverting terminal voltage If there is no -ve feedback, o/p acts ...
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MOSFET PWM issue

I want to dim an LED and have connected a P-channel MOSFET to switch the high side. I added a N-channel MOSFET as a driver. The schematic is attached below. I'm applying a PWM sine signal from an ...
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LTspice - Staircase saturation transformer

I am trying to simulate on a full bridge converter a staircase saturation transformer. I was thinking by adding a very little resistor on one leg of the full brigdge converter, it will in any case ...
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Alternator's saturation in load and no-load conditions

When a ferromagnetic material is exposed to a magnetic field in which it moves, some voltage is induced in the material. If you increase the magnetic field, the voltage is increased up to a point, and ...
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How does this transistor behave as the base voltage is increased?

Consider this transistor. How do the voltages Vb, Vc and Ve vary as we increase ...
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Is there a formula to calculate the saturation current of an inductor or is it only obtained experimentally?

I want to make an inductor for my buck converter since I cannot obtain the recommended inductors for the LM2596. How do I calculate the saturation current for this inductor if I use a ferrite core? ...
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How do I stop buck converter voltage from dropping whenever current increases?

I built this buck converter circuit using the LM2596T-5 (5 V OUTPUT, 12 V INPUT) using the exact components mentioned in the datasheet's first page (schematic below), except for the diode. I used the ...
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MOSFET in saturation mode

A MOSFET in saturation mode behaves like a constant current source but a current source has infinite output resistance. To make it work like an active load instead of a passive load like a resistor we ...
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Designing an automotive alternator's voltage regulator - how to avoid magnetic saturation in the rotor?

NB: See final edit. The question is based on a false premise Friends are making a test-bench for automotive ("Lundell") type alternators. They were supplied with an example alternator plus a ...
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Transistor collector emitter saturation voltage

I am trying to choose a transistor to use in a current mirror to prevent thermal runaway of parallel LEDs (yes I have to connect them in parallel. I know connecting in series or using separate ...
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BJT differential pair on breadboard enters saturation

I've built the following circuit on a breadboard (for the purpose of experimentation) and measured the voltages: IN+ and IN- ...
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Saturation for emitter follower

How can a transistor connected in emitter follower configuration be driven into saturation? I know that for saturation, the base voltage should be greater than the emitter voltage, but also than ...
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In the PNP transistor, base current is the sum of emitter and collector current. How is this possible?

The PNP transistor at the right side doesn't follow any characteristics of the 4 modes of operation of BJT. How is this possible? PSPICE simulation has shown quite similar results. Here, beta=100.
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Boost converter drive inductor into saturation

The boost converter I'm trying to put together might seem a little bit odd, as it's made out of parts that belong in a museum, but I've quite a lot of them so I thought to use them for something. I ...
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What is "level of saturation" for transistors?

This is a term I've never heard of, and it's presented on a work analysis of a ttl nor circuit. It basically says that the transistor that links the output with the ground should have a higher "...
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Why is there a large "well-shaped" distortion when the input voltage exceeds the power rails of an op-amp?

The specific model in question is the LM258 op-amp. After looking at its datasheet I understand why the output swing at both the positive and negative voltages, however I don't understand the physical ...
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What is the current flow logic of this NPN configuration [duplicate]

For a switch i need to put the transistor in cutoff to OFF and saturated for ON as shown in the lecture bellow. My input is a voltage source i need to control the base current to make the collector ...
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Why should BJTs be saturated in switching circuits?

Assume that I'm going to drive an LED with a bipolar transistor as a switch. According to books, when the LED is on, the transistor should be saturated, i.e. V_CE should be close to zero. But why do ...
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MOSFET terminology seems to vary in every article I read

For someone trying to learn about FETs, it seems there is no consistency in terminology (unless I am reading things wrong.) I am trying to understand the FET as a switch (for power applications.) It ...
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Harmonics in transformers

could you explain what it is that causes harmonics in transformers? I've read that these are the reasons, but it still doesn't give me a proper explanation. Saturation of the core Magnetizing current
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MOSFET on condition - Relationship between drain-gate voltage and drain-source voltage?

I am trying to learn the relationship between drain-gate (VDG) voltage and drain-source (VDS)voltage? From one of the QA readings in StackE, I understand that drain-gate voltage is less than drain-...
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Can I use a laminated silicon steel transformer core as a low frequency boost converter core?

Since laminated silicon steel is used in low frequency transformers, can't I also use it as an inductor in a low frequency boost converter, at maybe 100Hz, theoretically shouldn't this work as well as ...
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Non Inverting Op Amp output near power supply voltage when input voltage is at 0V

I have a simple non inverting op amp circuit. I am using this to amplify a DC voltage. The positive input voltage will vary from 0V-5V. My problem is that regardless of the input the output is about ...
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2 votes
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Detecting AC current using saturated current transformer -- variation in saturation ampere-turns of magnetic cores

In another question someone asked about using a transformer (in current transformer mode) to detect current through a power line. The purpose of circuit was not to measure the current, but was only ...
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1 answer
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Motor rewinding - saturation concerns

After reading a lot about 3 phase BLDC motors there's one concern that's nowhere to be found. Let's say that we have a 1000 Kv motor and we want to rewind it to 10 Kv to get unrealistically high ...
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Inexplicable curve shape of short circuit current measurement on synchronous machine

I'm doing some experiments on a synchronous machine with follwing data: nominal power: 5kVA nominal stator voltage: 380V phase-phase nominal stator current: 7.6A nominal frequency: 50Hz / nominal ...
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Does turning on inductive load (ex. AC motor) at peak input voltage reduce inrush current?

I was checking out the following project on hackster and at some point the author claims that When the load is predominantly of inductive type, the turn-on is performed at the peak of the input ...
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Preventing opamp from possible saturation maybe

I am trying to simulate a gyrator circuit for implementing capacitor as inductor in LTSpice. While simulation I am encountering the following problem : It seems that top left opamp undergoes ...
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1 vote
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Understanding the VI output characteristic of NPN transistor in the saturation region

I have trouble in understanding the VI graph of the output current (collector current \$I_C\$) in the NPN transistor. More precisely the common base one (this is the first type of transistor I came ...
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How to read MOSFET datasheet to determine when the MOSFET is fully on

I'm currently trying to find an N-channel MOSFET to act as a switch to be controlled by my Arduino, and I've come across two particular MOSFETS so far that seem like they would be a good fit to the ...
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1 vote
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How does forward biasing of both junctions in BJT leads to saturation?

As far as I know, for an NPN-BJT, when both (base-emitter and base-collector) are forward biased; we consider the operation to be in saturation mode. Here, the transistor functions as a short circuit ...
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Which transistor ratings do I use when calculating something?

Let's say I want to calculate VBE for a transistor (for example). What do I use? VCE (Blocked) or VCE (Saturation) or VCE (max)? Let's say I want to calculate Ic/Ib, what do I use? Ic/Ib (blocked) or ...
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1 vote
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What happaned when the flyback transformer is in saturation?

I am trying to design a DC-DC flyback converter. Input voltage is 110V and output voltage is 24V. I have used NCP1252A PWM controller. Flyback transformer windings: Primary -> 24 turns Secondary -...
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1 vote
2 answers
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Power inductor's staturation current for buck converter

Is it correct that when selecting an inductor for a buck converter I should be choosing an inductor with the saturation current higher than the converter's peak current? How much of a margin should it ...
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Calculate voltage drop across Linear MOSFET in saturation region

Considering the below schematic, how is the voltage drop across the MOSFET calculated when it is operated in the saturation region? I am trying to calculate the power dissipated by the MOSFET so that ...
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MOSFET drain current equation vs on resistance

I have a very simple circuit. It’s just an n-channel enhancement MOSFET where Vgs is being driven to 9V and a relatively small 9ohm resistor sits between the 9V battery and drain terminal. The way I ...
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MOS current mirror region of operation

The mosfet M1 is clearly in saturation as gate and drain terminals are shorted. Why we take M2 also in saturation? I know Vgs1 = Vgs2 and they are identical MOS but i cant justify why M2 should be in ...
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Transistor - Saturation and Active Regions

I am using this BC817-40 transistor as a switch. In the above image, we can see that inorder to operate my transistor in the saturation region, I need to make sure my Ic/Ib ratio is less than 40. ...
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Buffer op amp amplifier saturation

I have designed a buffer amplifier using an LM358 op-amp, with an input of a 1kHz sine wave and a power supply of +/-6V. whenever I increase the input sine amplitude above a certain threshold, I get a ...
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The meaning of constant current source in BJT

Taking a sample from TAOE Ch.2 Figure 2.9 for example. The book suggests that BJT constructs a constant current source for the LED and \$\beta\$ is subject to change from multiple parameters thus ...
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MOSFET regions of operation

Let's say I have a MOSFET already operating in saturation such that Vds > Vgs - Vth. Can I make it to operate in triode or linear region by simply varying the drain voltage such that now Vds < (...
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Current Mirror Circuit

Below is a sample current mirror circuit. I understand that If the transistor Q1 is connected in a diode connected BJT configuration and the Transistor Q1 and Q2 have identical transistor parameters, ...
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Buffer Clipping Below Negative Supply Voltage

I'm trying to understand op-amp operation, starting with the buffer circuit. I have simulated the voltage follower using an LM324 in Multisim Live. I was trying to simulate output saturation by ...
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How to calculate Ic for a very simple NPN transistor circuit

I built a very simple circuit with an NPN (2N3904) transistor. Then, I swept Vce from 0 to 5V and plotted a Vce vs Ic graph (as shown in the picture). I heard Ic = Is*e^(Vbe/VT), where VT=0.025V, and ...
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