Questions tagged [circuit-analysis]
Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network. Consider using in conjunction with tags for the particular analysis technique(s) in question: "nodal-analysis", "mesh-analysis", "superposition", etc.
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Do you know this circuit? [duplicate]
I was checking the flipper Zero Wi-Fi Developer Board schematics and in the power section I bumped with this circuit, but I've never saw it before. Someone knows the name of the circuit or its purpose....
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Why does a MOSFET fail on fast signals, even if they're much longer than the turn on + turn off times?
When running at a fast signal, why does the MOSFET below not turn off, even when gate voltage is well below threshold (even negative)? Although the signal is fast (7 MHz, 140 ns period) it is < 1/...
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RC Integrator Simulation
I am simulating an RC integrator using an ideal opamp.
I model the opamp as two different models (one with vcvs and the other with vccs) as shown in the below two cases.
When I ran the ac simulation, ...
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Why is a push-pull transistor configuration asymmetric?
Looking at the circuit below:
How do I analyze it? Specifically, why is the output able to go nearly all the way to +12 V but not beneath 0 V? I'd expect that when V(sig) < 0, since current flows ...
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How do I analyze an emitter follower with a capacitive load?
How do I analyze an emitter follower with a capacitor load?
At 7 MHz, a 1 nF capacitor has impedance of 22 Ω. A simple emitter follower with a 22 Ω Re is easy to analyze:
However, replace that ...
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What does a grid-cathode bypass capacitor on CRT do, and why is this one not doing it?
I have modified a (US) 1970s solid state B&W TV set for direct (NTSC) composite input for vintage computer use, in accordance with some equally vintage instructions specific to this set. The set ...
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How do I generate a trigger signal from a periodic analog signal having varying amplitude [closed]
I have an analog signal detecting a periodic vibration of low frequency (<100Hz) and want to generate a pulse whenever the signal crosses a certain threshold. The challenge is that the amplitude of ...
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Load cycler circuit analysis
Hello I am attempting to build a simple load cycler that will charge and discharge 3.7 V 18650 batteries for a certain number of cycles.
I would like to program it to do something like this:
I'm not ...
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Using Kirchhoff's voltage law for calculating S-parameters
Consider the following circuit:
for which I'd like to calculate the S-parameters of the impedance \$Z\$ (and assuming \$Z_G\$ = \$Z_L\$ = \$Z_0\$). Will it be correct to use the Kirchhoff's voltage ...
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Where am I wrong in my derivation of RC charging circuit equation?
I'm trying to derive the RC charging circuit equation for capacitor voltage \$V_C\$ and charging time \$t\$. Here's my solution,
We'll start by assuming the battery, resistor and capacitor are ...
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Why do some JFETs oscillate and others don't?
Below is a simple JFET Clapp Oscillator, which works quite well. It starts oscillating at around 40us and gets into clean, stable oscillation by 100us:
When I replace the J309 JFET with a more ...
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Need help with identifying a SMD part
Can anyone please help in identifying this SMD part marked with "CP6W"?
This is part of the power supply of a 8 inch tablet from China, "Chuwi Hi8 pro".
My findings as of now are:
...
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What is the purpose of the BJT in this circuit? [closed]
What is the purpose of Q1? Is it just to amplify the current? What region will Q1 be operating in and how do I determine this?
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Are inductors in resonant circuits dangerous? They produce very high voltages
A simple series LC resonant circuit has theoretically infinite voltage in the middle between L and C, if we assume 0 ESR and exact resonant frequency:
\$V_{at LC junc} = V_{in} \frac{X_{C1}}{X_{C1}-...
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Will a circuit oscillate at all its resonance modes or only the most dominant one?
Will a circuit oscillate at all its resonance modes or only the most dominant one?
Consider an amplifier with a feedback loop that meets the Barkhausen criteria at multiple frequencies. Will it ...
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Why does this two stage op-amp not work?
I was trying to simulate a two stage op-amp I had just learned about. I am going step by step i.e. as you can see from the schematic I have started with ideal current sources.
I know that this op-amp ...
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How can this Clapp JFET oscillate when its gate is tied to ground at the resonance frequency?
How does the circuit below oscillate? It seems to have |gain| < 1 at its oscillation frequency of 2.25 MHz, yet it oscillates there.
My analysis:
The DC path is through L4 only, allowing a bias ...
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Help with a circuit analysis problem
I have a circuit which gives me some strange results during simulation and I would like some help to analyse it. The circuit is the following:
Now, what I do is that I am watching the current values ...
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Where is the phase shift on this oscillator?
I didn't think the oscillator below could work, but I built it, and it does:
I used 10 uH for the inductor, 2.7 nF for the capacitor, and got oscillations around 8 MHz.
The feedback loop is a series ...
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How much current will a BJT transistor draw through its base?
If a BJT transistor has a voltage Vb at its base, its nominal emitter voltage Ve will be Ve = Vb - 0.7. If we know Re, we know the current through the emitter Ie = (Vb - 0.7)/Re.
If beta is high, ...
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Driving 2xP-channel MOSFETs with a single N-channel?
I would like get some feedback on the given subject. I want to control the N-channel MOSFET using a microcontroller and use 2xP-channel MOSFETs to increase the current capability.
What I'm doing as ...
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Determine the voltages Va and V1 for the circuit
I'm going through Boylestad 11th Edition and there is a question 37 b) on page 182 that I cannot get right. "Determine the voltages Va and V1 for the networks in Fig. 5.120."
So the second ...
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Multiple voltage source problem from Boylestead
Good day
I'm doing this problem from a textbook and I cannot understand how they got the answer. So I have to determine the voltages Va, Vb and Vab. There is a process to do this that I don't think I ...
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Transfer function of differential controller
I found an op amp circuit that is designed to be a derivative controller (D-controller)
simulate this circuit – Schematic created using CircuitLab
and the transfer function $$ \frac{V_o}{V_i} = ...
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Calculating current through a diode in a voltage divider circuit
I have a voltage divider circuit which I use to drive two LEDs with different luminous intensity. I understand that this is not the best way to do it but I wanted to control two LEDs with the same ...
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Detecting 12V using MCU
I am trying to detect a 12V input signal coming in from a DC wall charger using an STM8 microcontroller. I am using a voltage divider with 10k/2.2k :
First there is a 10K resistor in series with the ...
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How can these passive RLC circuits change a sinusoid's frequency?
Given a sinusoid input of frequency f, an RLC network, no matter how complex, should produce a sinusoidal output of frequency f, with possible attenuation and phase shift. At least that's my ...
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Do transistors "prefer" to pull current from their base or collector?
The circuit below is a simple BJT amplifier which behaves exactly as expected:
If I remove the capacitive coupling and voltage divider bias and replace it with an input offset, it completely breaks ...
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Switched Capacitor Non-Inverting Amplifier
I have been studying switched-capacitor circuits recently. I have come across one question with regards to the switched-capacitor non-inverting amplifier circuit shown below. It is made up of ...
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What requirements of a feedback network are needed to produce oscillation?
I'm trying to understand how to analyze simple oscillators, and would like to know if my conclusions about the required feedback network are correct:
The simplest way to build an oscillator is with:
...
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How to analyze and simplify a voltage divider with a second voltage source?
How do I simplify the circuit below?
simulate this circuit – Schematic created using CircuitLab
I know that R2 and R3 form a voltage divider, but I can't figure out the input impedance that In ...
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Cadence VCVS Output Limits
I am testing a vcvs and trying to use it as an ideal OP.
This is what I observed when I tried to set a "maximum output voltage" to the vcvs.
This is the simple vcvs schematic. VIP: AC=0.5, ...
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corroded contacts cured with WD40?
Does WD40 help fix corroded contacts in a plug or does it risk shorting them?
The airbag warning light in my car is on and I intend to fix it by squirting WD40 down the pug and socket.
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How do we measure inductance with a DC source?
I just got this question asked by a Staff Engineer for an entry-mid level job at a large company, and I suspect the interviewer might be wrong here. I had this interview on Monday and I got a ...
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How to solve non-ideal opamp circuit using feedback properties?
Is there a neat way to solve this using feedback properties? Or if you know a better method to solve this, please suggest one.
It would be straightforward if we assume an ideal opamp in this case, ...
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Norton equivalent current source direction in this circut
I want to convert R1 and V1 to Norton. What will be the direction of the current source?
Edit: As mentioned in @RussellH comment, "the current must enter and exit the same nodes before and after ...
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Understanding the components of backlight circuit of digital watch [closed]
I am not a hardware engineer. I studied basic electronics 15 years back in school days, so you can consider me a noob.
I have a digital watch in which all the features (time, alarm, chime, etc) work ...
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How can i sovle this mesh circuit by source transformation? If not, do we have nay orther ways? [closed]
Give the circuit as shown above. Detetmine E=? So that the 16V voltage source provides 32W power.
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Why are my results different from their PSRR scheme?
Even though I followed every step given in the Analog devices website, the results were still different and I don't know why. Can anyone give me a solution?
Here is my result:
But their PSRR ...
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What is the purpose of this circuit inside a solar lamp?
I'm trying to get started with electronics, just as a side quest. I found this little circuit inside a solar lamp I had. I'm trying to understand what its purpose is and why it uses its components, ...
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Verification of Initial Conditions in an RLC Circuit (buck converter, output voltage)
I had drawn the following circuit (note that all components are ideal and european standard):
Suppose the following Situation:
\$t<0\$: The MOSFET was open for a very long time
\$t=0\$: The ...
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Non-ideal active low pass filter for LV25P output
Hello everyone I need some help understanding the active low-pass filter below.
I was told to use this circuit to filter the measurements of the output voltage of an inverter, but there is no ...
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How do you utilize a voltage signal from a subcircuit when developing a larger circuit?
I am trying to understand how circuits are built. In my experience learning about circuits, I have learned all about analysis techniques for circuits that start with a complete circuit and ask, "...
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Finding Thevenin voltage and resistance [closed]
I am struggling to find the Thevenin voltage and resistance across terminals A and B of the given circuit.
I got as far as writing KCL at nodes 2 and 3, which gave this:
$$v_\text{AB} = - G_2/G_1 e + ...
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Why would changes in the impedance of a transducer affect the voltage displayed on the oscilloscope?
In my setup, a function generator is connected to an amplifier that drives a transducer. The amplifier output is connected to both the transducer and an oscilloscope via a tee connector.
I do not ...
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Verification of Initial Conditions in an RLC Circuit (buck converter, inductor current)
I had drawn the following circuit (note that all components are ideal and european standard):
Suppose the following Situation:
\$t<0\$: The MOSFET was open for a very long time
\$t=0\$: The ...
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Function of R6 in this voltage reference circuit
I've seen the following precision voltage reference circuit in schematic diagrams of several vintage instruments:
I understand how this circuit works in general: it is basically two constant current ...
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SRAM not writing properly after radiation exposure
I have an SRAM memory device GM76C88AL with this datasheet. The RAM was exposed to a radioactive beta source (~2MeV) for some time (about 2 hours). The source was just right above it (placed on it), ...
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3.3V regulator and Comparator not working as anticipated
This is my first time designing something like this so excuse my inexperience. My objective here is to create a simple circuit for checking if a particular component is good or has been damaged. From ...
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How can I find time constant of a RC circuit with a transistor circuit when switch is closed?
First of all maybe this a easy question but I am a beginner, so forgive me. I am having trouble finding the time constant shown in the circuit. How we analyze this?
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