# Questions tagged [ideal]

For questions about ideal components (voltage sources, diodes, op amps, etc.). Use in conjunction with the tag(s) for the ideal component(s) (e.g. use the "operational-amplifier" tag for questions about ideal op amps).

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### Assumptions in a ideal circuit which consists of ideal wires(zero resistance)

Let us say a circuit consists only of a battery and ideal wires. Assuming steady state, if we remove the battery and now complete the circuit with only ideal wires, is it safe to say that the ...
1 vote
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### How do I use ideal MOSFET model in LTspice? or How do I set voltage in node without voltage source?

I want to simulate the principle of 1T1C DRAM cell. But if I model voltage source in Bit line, bit-line voltage is set by its input signal. So I want to seperate bit line, using ideal MOSFET component,...
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### I made a 3-phase power rectifier circuit with "ideal" diodes. Is there anything I should change?

I made this 3 phase power rectifier with ideal diodes, instead of actual diodes. I basically just copied an ideal diode diagram and pasted it 6 times. It's for use on a wind turbine project, to ...
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### Why is collector current in a diode-connected transistor not subject to the non-ideality of the B-E junction that it must necessarily traverse?

In a recent comment I was asked why a diode-connected transistor behaves as it does. Jonk's answer here addresses this question, and explains that the geometry of the B-E junction in a signal BJT ...
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### Ideal voltage vs ideal current source - which one wins?

Here is an example 5.8 from Hayt "Engineering Circuit Analysis" - 8th edition (p.146). The goal is to find Thevenin equivalent faced by 1k$\Omega$ resistor. I am trying to solve it using ...
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### How does clamping circuit work when ideal diode is used?

I'm currently having problem in understanding the dynamics of capacitor when it is in connection with an ideal diode. In the circuit below we can see a sinusoidal source of 40V peak to peak and a ...
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### Factoring in rectification voltage drop when calculating ideal DC current

Under ideal circumstances, there would be no voltage drop across a rectifier. I wanted to know if it was possible to calculate ideal DC current when a load is connected to the rectifier. For the ...
174 views

### Solve the multiple ideal diode circuits problem

Find the Q-points for the diodes in the four circuits in Fig. P3.68 using (a) the ideal diode model and (b) the constant voltage drop model with Von = 0.7 V. Note that Resistor = 15kOhm The second ...
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### Usage of input voltages in ideal op-amp

Why is the difference between inverting and non-inverting voltages in an ideal op-amp equal to zero in many problems? I can't seem to get that. Let's say that if the difference voltage equals zero, ...
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### Special cases in ideal source transformations for equivalent cirucits

I don't exactly understand what's meant by these transformations. Are we supposed to replace one of the sources with a resistor? What's the resistor's value supposed to be? I couldn't find sources ...
1 vote
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### P-channel MOSFET + op-amp ideal diode

I'm replicating the ideal diode circuit from Crutschow. I'm using the op-amp flavor in order to get a very low quiescent current. The P-channel MOSFET will be a NTMFS002P03P8ZT1G. My questions are : ...
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### How do I turn off an LTC4359 using the SHDN pin?

I am attempting to design an Ideal Diode Controller for application in a 12 V automotive circuit using an LTC4359 as the controller. I want to implement the shutdown facility available with the ...
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### Ideal diode confusion

I am struggling with understanding ideal diodes and have reached my wit's end in trying to find where I am making a mistake in my assumptions about how these work. What I do not understand is that, ...
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I need to assemble a high precision resistor decade box. Among the reason is that 2 of them creates a very reliable voltage divider & that goes along with my plan someday to put together a ppm ...
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I'm assembling a capacitor decade box. It will be used to tune circuits both in power & high frequency electronics (but, probably not GHz RF; with all the parasitics). So, I need it to be as low ...
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### DIY ideal diode: What problems will I encounter with this circuit?

I have a 3.3 V LDO that I don't want to use for more than ~200 mA. I need 600 mA. I know that just putting them in parallel is a bad idea. Using op-amps and some sense/shunt resistors, I made ideal ...
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### Can an LTC4372 ideal diode controller drive multiple parallel MOSFETs?

I am designing an ideal diode circuit for back EMF protection and reverse polarity protection outputting on average 60 A from a 4s9p li-ion battery to run 8 motors. For this circuit, I used an LTC4372 ...
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### Ideal behavior of op-amps [duplicate]

I have been studying about op amps and there is something I can't get my head around. The thing is, when assuming an ideal op-amp, one of the restrictions we obtain is that the voltage in both the ...
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### Eliminating ideal voltage source for node analysis

I have a circuit that I would like to convert into a conductance matrix for the node analysis by inspection method. I have, however, run into a problem. I have this 36V ideal voltage source with no ...
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### Determining the voltage of 5 phase PMSM motor

As a part of the project, I have to design a 5-Phase PMSM motor, for which want to know the following: How to determine the voltage ? What should be the ideal voltage to use this motor in an electric ...
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### Question about ideal transformers and inductors

Recently I was studying about alternating currents and transformers and I got confused about some of the concepts. I tried a lot of sources but none of them seemed to address the problem. I ...
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### Ideal Battery in Circuit

Does Kirchoff's voltage law hold when we connect a single battery to a circuit that has no other components. If it does hold, kindly let me know how. If it doesn't, how do we reconcile with that?
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I was trying to solve this problem (number 27) and as per the KCL equations I am getting that an infinite number of Ammeter readings are possible. I used KCL after taking the outer loop as the ...
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### Confusion with impedance matching example using an ideal transformer

Starting from "The Effective Resistance of a Load Resistance attached to a Transformer" at page 8 of this document there is an example where it demonstrates impedance matching using an ideal ...
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### Ideal Op Amp Circuit

I have a question about the circuit below. I want to find Vo in terms of Vi. But I don't fully understand the principles about an ideal op amp's output. You will see my questions in bold at the bottom ...
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### How is voltage divided between two reverse-biased ideal diodes?

Suppose we have two identical ideal diodes (without any resistance or voltage drop). We connect these two diodes in series, in the same direction, and reverse-bias them with voltage V. Now we have two ...
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### Average power of load connected to an ideal transformer

Where does the 1/2 come from in the power equation?
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### Finding indication of ideal ammeter

Would anyone share some tips, advices for solving this task? So far, I have dealt with far simplier electric circuit's tasks. This is new to me. Any kind of help or advices are appreciated, thanks!
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### Combining perfect voltage and current sources

I am attempting to reduce the circuit shown into a form of a single voltage source and resistance in series using Thevenin and Norton conversions. I approached the problem by first considering a ...
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### Ideal Transformer Theory Question

I have some questions regarding ideal transformers, similar to the one seen below: When talking about 'ideal transformers', can I calculate the current on the primary side by finding the complex ...
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### Ideal switch acting on a capacitor

Let's consider this circuit: and suppose that the capacitor C1, charged at the input voltage Vin, at time t=0 is connected by the switch to the virtual ground. Assume also that C and C0 are initially ...
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### Schmitt trigger with 741 op-amp not behaving as in simulation

I am implementing a Schmitt trigger using the circuit shown below. This circuit consists of one LM741 op-amp, which acts as an asymmetrical Schmitt trigger with a single power supply. According to ...
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### Maximize output signal swing in digital circuit design

Please help me understand the following paragraph in chapter CMOS Digital Logic Circuit from book"Sedra/Smith micro electronics circuit 6e". An ideal VTC is one that maximizes the OUTPUT signal ...
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### At what resistance can a real inductor act like an ideal inductor?

So it's my understanding that an ideal inductor with a constant voltage applied should have a constant ramp for the current through it (a triangle wave), but an inductor that's not ideal (with ...
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### Symbol for ideal voltage source vs symbol for real voltage source

Wikipedia's article on Voltage source shows the figure below. It says in the figure that the following symbols is an ideal voltage source. However, elsewhere in the same article they have a circuit ...
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### How to represent the variation of electrical resistance with frequency for ideal circuit elements?

Can anyone please help me a little and guide me through representing the variation of electrical resistance with frequency for an ideal resistor, coil and capacitor. I will do all the work I can ...