Questions tagged [circuit-analysis]

Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network.

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A question from Sedra/Smith Microelectronics

regarding question 1.12 from Sedra and Smith MicroElectronics book (2009 international edition): A transducer characterized by a voltage of 1V rms and a resistance of \$1M\Omega\$ is available to ...
4 votes
2 answers
9k views

Zener Noise Generator - NPN BJT Amplifier Analysis

I'm interested in creating a low voltage white noise generator by means of a zener diode, as detailed here: Zener & BJT Noise Generator. Specifically, I want to use the circuit here, in order to ...
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4 votes
6 answers
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Voltage drop assumption on diodes (LEDs, etc.)

I've always wondered why is it valid to assume some voltage drop (different from the junction voltage drop) on diodes or LEDs from the power up of a circuit. It simplifies the analysis, but it's ...
10 votes
1 answer
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How is this 5-24V input circuit working?

Since I require some kind of wide range input (going to a microcontroller) for a new project, I looked through some designs that are already in use (or were considered at some point) for other ...
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1 answer
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Solving electrical circuit with two voltage sources

I want to participate with the physics olympiad. I encountered a question with usual electronics but two voltage sources (!?) and I had to calculate the voltage / currents / resistance values of that ...
2 votes
1 answer
950 views

Simplification of a circuit

Is it possible to simplify the following circuit? My goal is to preserve as fewer nodes as possible since the number of nodes substantially affects the complexity of my further computations. The ...
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4 votes
3 answers
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No output being measured on transimpedance amplifier

I have been playing with a SFH 213 photodiode (the clear one) and I've hooked it up to a TLV2371 op amp so as to resemble an ordinary transimpedance amplifier. I've varied the feedback resistor ...
1 vote
2 answers
2k views

Voltage between two terminals of an open circuit which's connected in series with a current source

simulate this circuit – Schematic created using CircuitLab What will be the voltage between nodes A & B? My guess is that the voltage between nodes A & B should be increasing forever ...
2 votes
2 answers
3k views

How can I solve a circuit of resistances with both a voltage and a current-source in between them?

If I have a circuit that consists out of multiple non-parallel/serial resistances with current/voltage sources in between them like the one below How can I solve a system like that (in this case for \...
22 votes
4 answers
65k views

Do electrons actually flow when a voltage is applied?

It's said in books that a circuit is a closed path and thus that electrons come back to the source. If that's the case, what would happen when there were an earth fault in a circuit? How would the ...
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1 answer
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Post-Transformer RMS Voltage for This Circuit?

I am confused here. For the below circuit: simulate this circuit – Schematic created using CircuitLab Ripple voltage is given as 1V peak to peak, Vo = 15V DC. I have assumed a 0.7V drop across ...
1 vote
1 answer
376 views

How to analyse such circuit with op amps?

V(вх) is input voltage, I need to find output voltage(in the center). Yeah, it must be amplifier, of course. Just, I know and understand how to calculate simple non-inverting, inverting circuits with ...
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-1 votes
2 answers
785 views

How do you make a shift/scale circuit using a transistor, resistors and a voltage source?

Given a resistive element that fluctuates between 0 and 10kOhms, a PNP transistor, a 20V source and a bunch of resistors, is it possible to construct a circuit with an output voltage as follows: 1) ...
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7 votes
2 answers
8k views

Understanding why use Laplace transforms for circuits

I am an Electrical Engineering student and in my Circuits class, I learned that using Laplace transforms is helpful while analyzing circuits. I see how it makes our calculations easier but I still don'...
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1 answer
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beginners book on analog circuits [closed]

As a scientist, I have a good theoretical grasp on the quantum mechanics behind a diode/pn-junction, capacitors, inductors etc.. however, I have practically no hands-on experience with designing an ...
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2 votes
2 answers
676 views

Phase Angles in Series/Parallel networks

INTRODUCTION: I've been having a hard time in class trying to understand phase angles. I understand a few concepts which I've stated below for clarity in regards to this discussion. 1.) Inductors-->...
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3 votes
1 answer
289 views

How to match this given circuit to a model for a simulation?

I have to simulate the electric field within a gas filled discharge gap generated by a radio frequency voltage generatio. The circuit, provided to me by the experimentators somewhat far away, is given ...
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7 votes
3 answers
11k views

What is the purpose of capacitors and resistors in this USB bus?

Trying to understand the purpose of the capacitors and resistors in this bus powered configuration for the FTDI chip, I think the capacitors are for filtering high frequency noise, not sure what the ...
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1 vote
1 answer
209 views

Reason for certain steps in Circuit Analysis

The image is from this lecture.The instructor Prof. Shanthi Pavan says that the part encircled in orange can be replaced by a voltage source with current through \$v_1\$ as \$i_1\$ and not \$i_1 + I_1\...
4 votes
3 answers
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How exactly does switched capacitor system work, what exactly is the detail of the primitive that switches

I have been seeing these switched capacitor circuits for some time now and have even seen Z-transform being used to model how these circuits behave. While I can see that there is some capacitor that ...
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1 vote
2 answers
763 views

How to use integration or differentiation to optimize frequency in achieving a specific phase angle?

Question: With source voltage kept constant at 8V peak to peak vary the frequency until the phase angle "theta" Vr referenced to Vs is approximately 45degrees. Record the Vpp value across R1 and the ...
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4 votes
3 answers
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Measuring transistor beta (hFE) - Ib anomalies explanation needed

I've been struggling with details of building accurate (\$\pm1\%\$ tolerance maximum) beta meter. The simplest idea I came with went to a diagram as shown below, with R set to a value providing a \$0....
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3 votes
1 answer
1k views

transistor loop to limit the current

I am trying to implement the DALI TX/RX circuit below. The description says: The other transistor (T2) is controlled by the current flowing through the resistor (R1). If a DALI slave unit is ...
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11 votes
2 answers
9k views

Inductor equivalent of capacitor's charge

Because inductors share similar equations in their charging/discharging cycles, I am wondering if inductors have something like charge. Capacitors have capacitance and charge while an inductor has ...
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1 answer
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non-inverting schmitt trigger op amp - replacing a zener diode on the input

I wonder if it is possible to replace the second figure below with the first one? Would both Vo output be the same on the figures below? If they are different, ...
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2 votes
2 answers
2k views

XML schema for electric circuits

Is there any XML schema to describe electric/electronic circuits? I am thinking of something like a netlist, but using XML markup.
5 votes
4 answers
11k views

When use Voltage divider in circuit analysis

I am trying to find the voltage in R2 with voltage divider, this is the schematic: simulate this circuit – Schematic created using CircuitLab but I can't, and I don't know how to apply the ...
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8 votes
3 answers
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Under what conditions should we use negative voltage?

As mentioned in the title I'm curious and confused under what circumstances a negative voltage should be used? Does it mean in a negative voltage power supply the current is flowing from ground point ...
2 votes
3 answers
769 views

Thevenin Equivalent Circuit

QUESTION: I'm having a hard time figuring up what the Thevenin Voltage is along with Thevenin Resistance for this circuit below. I'm also confused on what I'm suppose to do when there is a current ...
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2 votes
1 answer
446 views

Finding values of LRC circuit when frequency is given

I am trying to solve the following question. The original question is: The given impedances of the series LRC circuit are established at an angular frequency of 2000 rad/s. Calculate the ...
1 vote
1 answer
277 views

Amplifier circuit - NMOS mode of operation? Gain?

Ok I have the following circuit, with values of variables: \$\displaystyle R_{1} = 1 M\Omega, R_{2}=10k\Omega,~~ k_{n}C_{ox}\frac{W}{L}=1mA/V^2\$ , and \$V_{T}=1V\$. 1) When \$v_{IN}=0\$, calculate ...
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1 vote
0 answers
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About a homemade SLA battery charger

After assembling a simple emergency light kit, it's time to build the battery charger. Details: Most of the time, the battery won't be used and the circuit will be always connected to the energy ...
1 vote
1 answer
365 views

Calculate current in branch using Thévenin's theorem

E1 = 20 V E2 = 5 V R1 = 10 Ω R2 = 20 Ω R3 = 10 Ω R4 = 10 Ω R5 = 5 Ω Calculate Ix. It's obvious that the Thévenin's theorem should have been used, but the implementation is a bit confusing ...
1 vote
4 answers
3k views

Circuit analysis with nodal analysis

[EDIT] I'm going to give mesh analysis another go, and see where that gets me. [DOUBLE EDIT] Mesh analysis didn't get me anywhere :( Im tearing my hair out over this problem, so any help would be ...
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1 answer
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Help me in understanding the circuit [closed]

I want to understand this circuit. The Circuit: My experimental layout: Question : According to the circuit.. It mentions that the "The Thermal Pad is to be connected to a Ground Plane (GND, ...
1 vote
1 answer
1k views

Find Vo in an op-amp - transistor circuit

I have a schematic with this system and can't find out how it works: simulate this circuit – Schematic created using CircuitLab How do I find Vo in this network? Please explain it "for dummies"...
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3 votes
3 answers
3k views

Checking materials (cheapest possible) to be used for a solar dark-detecting LED light bulb circuit

I want to make this circuit, which is from evilmadscientist.com and includes a Joule Thief: It's for a solar dark-detecting LED light; and I'm trying to follow this guide: https://www.instructables....
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6 votes
3 answers
762 views

Solving this op-amp circuit

I would appreciate some help solving the following circuit. I've been trying for a very long time and can't get the same answer the book has. I'm trying to get \$ V_o \$ in terms of \$ I_{os} \$. ...
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1 vote
2 answers
887 views

Basic circuit analysis - diferential equation

This is the circuit I got from an example in a book "Practical Electronics for Inventors", on page 48: How can one understand that \$0=R\frac{dI}{dt}+\frac{1}{C}I\$ implies \$I=I_0e^{\frac{-t}{RC}}\$?...
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3 votes
1 answer
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Is there a way to create a 2 bit / 4bit memory element using Flip Flop?

I have come across Flip-Flop memory elements & it seems really cool, So far i have only did Set, Reset Using Flip Flop, I am eager to know that Is there a way to create a 2 bit / 4bit memory ...
5 votes
3 answers
2k views

Circuit Analysis With Non-Ideal Diodes

I have seen how to do circuit analysis with ideal diodes, that is replace forward-biased diodes with connections and replace reverse-biased diodes with gaps. But the problem is that I want to know how ...
2 votes
2 answers
795 views

How can I improve my Freq to Voltage circuit?

I had a term project which was based around Analog-to-Digital convertors. We used anLM2907 Freq-toVoltage convertor to take a 150mVpp sine wave (0- 1kHz) and convert that to a voltage. The voltage ...
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4 votes
2 answers
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How to find Thevenin resistance of circuit with voltage source and three resistors?

The question is: Replace the circuit with a Thevenin Equivalent Circuit and find the Thevenin Resistance (Rt) in ohms. I've used Thevenin before and solved quite a few equivalent circuits as well. ...
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2 votes
1 answer
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How to efficiently compute the current at each node in a resistor network

I encountered a academic research problem to efficiently compute the current/voltage at each node of a rectangular resistor network. The rectangular resistor network that I have is defined by two ...
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2 votes
4 answers
194 views

Resistor and heat

Due to a power supplier manufacturer chanege the BOM lately, it require now more current to be drawn (need more load on my circutry side). I added a resistor in order to draw more current from the ...
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3 votes
1 answer
995 views

PSpice homework Question

I'm having trouble with this question. Can somebody help? I know the equation for part a) is: $$P_{\text{max}} = \frac{1}{4} \cdot \frac{\mid{}V\cdot{}t\cdot{}h\mid{}^2}{R_\text{L}}$$ And I'm sure ...
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Format Approach to NODAL ANALYSIS

SITUATION: Nodal Analysis is nothing more than applying KCL and is very powerful. I'm working on developing a more clearer perspective of two approaches in Nodal Analysis "GENERAL & FORMAT". Mesh ...
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3 votes
1 answer
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How to apply the Barkhausen criterion in order to know if a system will oscillate?

How to analyze or apply the Barkhausen criterion for oscillation of the astable multivibrator below? The criterion talks about the magnitude of the products in a loop must be equal to 1 (ideally) The ...
1 vote
2 answers
511 views

Circuit breaker selection that can be tripped with a microcontroller

I am designing a system that will simulate an upstream fault with a micro-controller action. the micro-controller will send a signal to a circuit breaker to simulate a line to ground fault(just like ...
3 votes
5 answers
528 views

Solving a circuit with a directional loop

I came up with the following circuit: Please disregard the labeled values in the diagram - the resistances are identical for the sake of simplicity, and of value \$R\$, and the voltage has value \$V\$...
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