Questions tagged [circuit-analysis]

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

Filter by
Sorted by
Tagged with
3
votes
3answers
290 views

Why can you define closed loop gain when return ratio approaches infinity like this?

This is from this lecture video. Please check the video link if you're not familiar with the terms. I can explain it but I think the video lecture is pretty good at it. Because the feedback amplifier ...
3
votes
1answer
388 views

Switching the high side of a load - The Art of Electronics

I am going through The Art of Electronics Third Edition. There is a note 12 unter Figure 2.10. Why Q3 would not switch if R3 = 100 Ohm?
0
votes
0answers
50 views

Can we look at only the voltage specification of a product? [duplicate]

I saw this specification in the product I wish to buy. Does that mean if I connect a 12V voltage supply from a battery, the current will actually be 5.8 A by default since the resistance of the device ...
3
votes
3answers
190 views

Understanding battery protection IC

I'm trying to understand an IC for battery protection, code HY2111 (datasheet) The internals are: And usage example is: My doubt is the part of the over-current protection. How this circuit is able ...
0
votes
1answer
69 views

Forward bias or reverse bias

What do we take, the flow direction of electronic current or conventional current through a diode if forward bias?
0
votes
4answers
134 views

Please help me understand the reason for using this 5V battery and 2k resistor at the gate of this MOSFET

Please help me understand what that V3 source and 2k resistor are doing here. The output from the comparator U4 will form the gate voltage of MOSFET. Because of the 2k resistor, the voltage at the ...
-3
votes
1answer
95 views

Is there any way to simplify this circuit? [closed]

I am trying to get the Voltage across R2, R5. Could someone explain with detailed steps? Thanks
1
vote
4answers
578 views

Does the electric potential of a closed-loop circuit maintain a constant value?

This question is related to the electric potential of a circuit point, not the voltage between two points. Here is a sample circuit diagram with \$V_{circuit}=5V\$ and \$ R_{circuit}=5 \Omega \$. If ...
0
votes
0answers
28 views

How can I relate input voltage, load voltage and reflection factor r?

I am given a circuit as given below. I have to find the relation between \$U_2\$ , \$U_1\$ and \$r_a\$ (reflection factor). I couldn't find the expression containing only these three terms as given ...
0
votes
3answers
119 views

Thevenin equivalent or mesh-current in a diode circuit

I've been stuck on a problem for a couple days and many hours now and see no other option than to ask here and see if you can help me or give me a lead. What I have been stuck on is this: My initial ...
0
votes
0answers
35 views

Tradeoff between (op) amplifier voltage range and offset and settling

I know that an amplifier (let's take an op-amp) can't swing rail-to-rail. The reason has to do with the load device. For example, in a normal common gate/common base amplifier, the load device causes ...
0
votes
1answer
95 views

Jump in RC current response to a square wave

Periodic square wave feeding an RC circuit: I am currently studying RC filter response to a square wave input with a period of \$ T_1 + T_2 \$. I have understood about voltage expressions and current ...
0
votes
1answer
86 views

Reason for using small sampling resistors in voltage measurement circuits

The above schematic is of the ZMPT101B module (current type voltage transformer) collected from Arduino Forum. All of the modules available in the market use a similar type of circuit having two ...
0
votes
1answer
49 views

RL Transient Analysis confusion

simulate this circuit – Schematic created using CircuitLab When I am using Thevenin's circuit and deriving inductor currents equations i am getting different Time constant \$ \tau\$ from what I ...
0
votes
0answers
38 views

Power delivery, purpose of capacitor? [duplicate]

I see this circuit design a lot in systems that require a sensor, a microcontroller, or other devices to be powered (with 5V for example). In the attached diagram, if V1 is my power source supplying ...
2
votes
4answers
211 views

What is the small signal gain for this circuit?

The question looked easy at the first sight. I found the quiescent current through the BJTs. I can say that |Vbe| = 0.7 V for both BJTs. Therefore, current through 1 kΩ below Q1 = 2 mA. Similarly, ...
0
votes
1answer
82 views

ESP12E : GPIO01 & GPIO02 Usage

I'm making a circuit for driving Relays, LED's from push button and few other functionalities from ESP12E module. for which I'm using simple Transistor driving circuits as shown in image. In this I'm ...
0
votes
1answer
122 views

How to calculate the real output voltage of a rectifier circuit (center tapped rectifier)

In my class, we are using Proteus 8 to simulate simple rectifier circuits. We are not familiar with analog electronics yet. Since the class is all about using engineering software, there are not many ...
0
votes
2answers
94 views

How to write transfer function is s-plane of single bridge rectifier?

I am trying to write a transfer function of single phase rectifier so I can use in Matlab to look for phase margin and gain margin: here an example I took from Circuit-lab I could write the transfer ...
0
votes
1answer
44 views

Modelling ESR of a parallel plate capacitor

I am trying to model a parallel plate capacitor (on die capacitor generated using metal plates.) I know the capacitance per unit area, and metal sheet resistance. No knowledge of the dielectric. I ...
0
votes
2answers
95 views

I am struggling to understand how to show the cut-off frequency

I understand that the cut-off frequency f = 1/(2πRC) or 70.7% from the maximum. The issue I have is I don't understand how these end up being 2 different points on my graph. Above is the cut-off ...
0
votes
2answers
45 views

Changing regular momentary switch to a motion detector in staircase timer circuit

(Reference image below) I have a classic staircase timer circuit ("TC") where any of the momentary switches will trigger the timer to power all the bulbs. Now I want to replace one of the &...
4
votes
3answers
756 views

How can I solve this simple BJT circuit?

Looking at this circuit (first circuit): Choose a value for V2 between 0V and 10V. Then how could we know the IB, IC, IE, VB, VC, VE? Can we solve it by hand (by hand means the value IB, IC, IE, VB, ...
0
votes
0answers
58 views

Test Input Transformer with Signal Generator

I have an RF Amplifier kit that is not working. The main problem is that the input transformer presents the radio with a high, unexpected SWR. It does amplify, so something works. The transformer is ...
0
votes
3answers
103 views

LEDs combinational circuit series and parallel

I have a project involving lighting up 12 dual LEDs using a 9-Volt DC Power Adapter with Max current of 500 mA According to the datasheet Dual LEDs datasheet the forward voltage is about 2 V at 20 mA. ...
0
votes
1answer
35 views

Wilkinson Divider with one shorted and open port

I have the following setup: It is my task to calculate the only value (\$S_{11}\$) of the scattering-matrix of the resulting one-port. Here is my idea on how to do that: From the left port and ...
0
votes
2answers
96 views

What would be the Open Circuit Voltage and Thevenin Resistance in this Circuit?

I am hoping someone can help me understand Open Circuit voltage and Thevenin Resistance. To test my understanding I created the attached circuit and ran a transient analysis using LTSpice. With a ...
3
votes
3answers
418 views

How do you divide gain for the first and second stages of the two stage opamp?

For this two stage opamp, how would you divide the gain for the first and second stage? For example the target gain is 2000 V/V, then you would have many option to divide the gain like 45/45, 30/70, ...
1
vote
1answer
44 views

Calculating N-type enhanced MOSFET gain with two different equations brings me a different result?

Hi, take a look at this problem from my notebook. Leave alone the fact that the resistor should actually be 1,111.111, it is not related. If they claim that VGS=2 and Vs is connected to ground it ...
1
vote
2answers
75 views

Joining two parallel branches with a wire

In the above circuit (grounding the negative terminal of the battery,) will the potential at C and D be the same? According to my physics teacher, the potential is the same at the two points. Why is ...
0
votes
1answer
32 views

Help understanding current sense application note to inject feedback into buck converter

I am trying to understand this application note using MAX4173H to inject feedback into a MAX1692 step-down converter. How to they determine the precise point at which the current limit will kick in, ...
1
vote
0answers
75 views

Super weird multimeter behavior, multimeter is jump starting circuit

So I have a custom PCB for a project that has an output port for a pump. The pump is rated for 8-24 VDC, 3-35 W, .3-1.5 A. The starting voltage is 9-13.2 VDC. The PCB is powered by a 24V power supply. ...
1
vote
1answer
104 views

Analysis of DC-DC converter with bidirectional power flow

Let's assume that Vin is a DC battery and Vout is a spacecraft main power bus. It is given that this circuit is DC-DC converter with bidirectional power flow. But to me this circuit exactly looks like ...
2
votes
2answers
133 views

What is the op-amp output voltage for a voltage-controlled current source?

I am trying to analyse the voltages in a voltage-controlled current source. What I have so far: Vin = V_C V_B = Vsupply - I_shunt*R_load However, I don’t know how to find an equation for the op amp’...
0
votes
1answer
88 views

Help with AC analysis

Can someone help me solve this? The answer is at the top right: This is what I tried; can someone show me what is wrong?
0
votes
0answers
40 views

How to block DC offset voltage on a potentiostat output?

I have an AUTOLAB potentiostat: working electrode (WE, Pt wire), counter electrode (CE, Pt wire), reference electrode (RE, Ag/AgCl solid state). I would like to capacitively couple the potentiostat ...
0
votes
1answer
111 views

What is this binocular transformer and how do I model it in LTSPice, Have High SWR In Ham Radio

I purchased this 70 Watt Amplifier Kit and built it. Unfortunately, the kits do not come with any instructions. I have managed to find a variety of web sites where people built the amp and offered ...
1
vote
1answer
53 views

Why I am seeing small voltage in the voltage display from detector?

I am using this detector to detect the brightness of an LED (powered and controlled by controller). When I use this multimeter to measure the detector output, I see the range of detector from 0-12.13V....
0
votes
0answers
114 views

Difference between unbalance load connected to grid vs isolated generator

Given two cases as following- CASE 1 An isolated 3-phase synchronous generator in star connected to a star-star 3-phase transformer and then secondary of transformer is connected to a highly unbalance ...
2
votes
1answer
66 views

Weird result when finding ripple bounds of RC circuit with square wave input

If \$V_{ext}\$ is applied to a RC circuit, then voltage across capacitor is given by: $$v(t) = V_{ext} + (V_i -V_{ext})e^{-t/RC} $$ Using above to find the ripple bounds \$v_l\$ and \$v_h\$, get two ...
1
vote
1answer
100 views

Why is \$V_{\text{ov}}\$ not a good design parameter?

Can anyone explain why \$V_{\text{ov}}\$ is not a good design parameter here? I understand why \$C_{\text{gs}}\$ is bigger (low bandwidth), but still can't understand the conclusion they made. Source:...
1
vote
3answers
117 views

Why is \$V_o=-V_c\$ in this circuit?

Why is \$V_o=-V_c\$ in this circuit? Is it a derivation from Kirchhoff's voltage law? simulate this circuit – Schematic created using CircuitLab
4
votes
3answers
1k views

How to handle four resistors in a square (OP-amp)?

I want to analyze this circuit and find \$\frac{V_{out}}{V_{in}}\$. But how should I handle the four resistors in the square? simulate this circuit – Schematic created using CircuitLab Can I ...
0
votes
2answers
101 views

Is there any straightforward simplification for the attached DC-Circuit

Simplifying a DC circuit would start by collecting the parallel resistors or the ones in series, for this circuit, I do not see any simplification, Am I right? My end goal is to calculate the values ...
1
vote
1answer
182 views

Component identification - Power supply circuit component exploded

I am fixing the power supply board of a big mobile sound system. Skytec PA-200 - sadly I could not find any schematics or more information on it. Unfortunately not only an electrolyte capacitor but ...
0
votes
2answers
134 views

Trouble Understanding Dual Transistor Flashing Circuit [closed]

I am having trouble understanding how this circuit works. I've breadboarded it out and the LED flashes but I can't seem to wrap my head around how the NPN vs the PNP is creating the flash. Any help is ...
0
votes
0answers
53 views

Thévenin Equivalent in a Circuit

I came up with the following problem that asks to find the Thévenin equivalent of the circuit below. However in the manual solution, I found that the author uses 1A for the a to b branch, and I have ...
0
votes
0answers
41 views

Reading button state of self holding is high all the time

I have a self-holding circuit for a push button that is used as the power button for a 7.4 V supply. The button state should be read by a PI4IOE5V9539 port expander....
0
votes
0answers
43 views

Is there any way to model an equivalent impedance value for an opamp? (not talking about input or output impedance, want a single value impedance)

I am trying to analyse the following circuit, and it has an opamp(TLV9002) in the feedback loop of opamp TLV07. It would be helpful if I can approximate the TLV9002 opamp as an impedance parallel to ...
0
votes
2answers
160 views

Input impedance of emitter follower

I decided to calculate the input impedance of the following emitter follower circuit as a practice. I used this well-known small signal model for the BJT: For voltage gain, I obtained $$A_\text{v}=\...

1
3 4
5
6 7
106