# Questions tagged [transient]

A change in an electrical system from an equilibrium or steady state. The response of the electrical system to a transient is its transient response. Examples of transients include load transients (in which the load suddenly changes) and line transients (in which the input voltage of an electrical system suddenly changes). The electrical system may require protection from certain transients, e.g. by using transient-voltage-suppression (TVS) diodes.

306 questions
Filter by
Sorted by
Tagged with
261 views

### Diode reverse recovery time and the speed (snap back) in which recovery takes place

I'm looking at generating a circa 1 nano second current pulse by utilizing the snap-back time (usually measured in the tens of pico seconds) when a diode is "forcibly" reverse polarized ...
• 384k
37 views

### Abnormal source voltage of a buck converter

I'm currently making a buck converter with a rated output of 60V and 10A. For its driver, I'm using TLP250 with Arduino as its input. The switching frequency I'm using is 20kHz. You can see my driver ...
• 99
44 views

I'm facing a doubt in transient simulation in ADS. In many setups I've seen placing a resistor in series to the transient voltage step generator. Placing the series resistor, and simulating the below ...
• 85
51 views

### Can I power my microcontroller system directly from a 3V lithium coincell (transient consideration)?

My device has to be powered with user replaceable 2032 coincell. I have a ~3.3V microcontroller like nrf52832. Its datasheet says: So lithium coincell voltage range (3.3V - 0V) is in operating ...
• 63
43 views

### Transient analysis for circuits with AC excitation using differential equations

In the process of finding transient response for circuits with AC excitation using differential equations, we use the method of complementary functions and particular solution, but I read earlier that ...
27 views

### Difference between Harmonic Balance and Transient solver in ADS

I am performing a simulation of a half wave rectifier (HWR) in ADS. I had developed a MATLAB code for Harmonic balance solver and Transient solver in MATLAB. The code gives comparable results when ...
• 61
83 views

### Series capacitor not blocking DC voltage

In my understanding a series capacitor (with some resistance) works as a DC block, essentially forming a high-pass filter, blocking DC. Under this assumption, a unipolar square wave of amplitude V ...
• 534
47 views

### LTSpice RL circuit simulation with ideal inductor and inductor from database

I am trying to simulate a simple RL circuit as shown below, the top one using inductor from the component library and the bottom one is picked from the database. Below is the properties of L1 ...
1 vote
38 views

### how does AC coupling eliminate the ground current problem between data source and destination in FPD_Link II I/F?

Reading about FPD-Link II in Wikipedia, I came across this statement for which I need clarification: Because the signal is DC balanced the application can use AC coupling, which eliminates the ...
• 576
24 views

### Is the power frequency characteristic of a network almost constant?

When a transient phenomenon happens in an electric power grid, the network reacts to this deviation with a power-frequency characteristic (MW/Hz). Reading the following paper ''Analysis and ...
36 views

### TRIAC protection for general domestic use

I am designing a smart switch for switching 220 - 240 VAC outlets for domestic use at a maximum of 16A. The load could be a washing machine, a toaster, a vacuum cleaner or any general home appliance (...
1 vote
125 views

### How to add unit function u(t) - u(t-2) as voltage source in LTSpice?

As far as I know, we put the unit function as PULSE in LTSpice. If we have b.u(t) where b is a non zero integer, then we can put it in Von. But what if the function is u(t)-u(t-2)? And what if we want ...
• 21
1 vote
103 views

### Output voltage of capacitor discharged in other capacitor?

Considering this circuit. How can I compute the maximum voltage across the resistor ? In this example, the capacitor on the left is initialy charged with 10 V. The second capacitor (on the right) is ...
• 147
58 views

### Explanation of the transient in an integrator circuit

Using LTSpice I have simulated the following circuit. It is a circuit integrator using the op-amp model: LF356. The simulation has a saturation voltage of 12 and -12 V and a square wave input source. ...
40 views

• 121
49 views

### fitting using unstable poles

I am trying to take into account the frequency dependent behavior of R and L in an LTspice simulation. So I fit their frequency behavior using Vector fitting technique and deduce the equivalent ...
• 309
639 views

### Purpose of reverse biased diode in pulse generation circuit

(Caveat: "young player" at large here.) The circuit below (not my creation) debounces a push button and generates a 1us negative pulse when it's pressed. I breadboarded it and it works as ...
• 133
80 views

### Calculating capacitor voltage with initial conditions in an RC circuit

If the initial voltage of the capacitor at 0s is 20V, would the equation for the voltage of the capacitor at a specific time be; 60 + (20-60)e^(-t/RC) or would it be 80 - 60e^(-t/RC)
• 45
58 views

### Transient behaviour of capacitor discharge [closed]

As far as my understanding, I think of a decaying exponential curve of a current in the case of a capacitor discharging. But sometimes (not sure on this), it shoes a damping waveform -- there are some ...
201 views

### What is the time constant for this circuit?

In this practice problem, the book apparently got the value for the time constant to be 0.1ms. This means that it only considered the 100k resistor to be the Rth. Why is the 10k resistor ignored? ...
• 95
72 views

### Measuring extremely small inductance (pH) with transient pulse response

I've made an inductor device. It has 2 terminals. It has inductance, resistance, and some parallel interwinding capacitance. I am using a Keysight B1500a semiconductor probe station, which has ...
• 73
49 views

### Transient generator simulation torque fluctuation (Ansys Maxwell)

while simulation for a PM axial flux generator at no load 1000RPM in Ansys Maxwell, shows moving torque fluctuating between -0.7 to 0.7 Nm, which should have been 0, as there is no load attached and ...
161 views

### Short-circuit current through disconnected capacitor

I have a large capacitor made of two smaller 200V rated 560uF capacitors. If I charge this capacitor to 30V with 4.5A from a bench power supply and disconnect it after around 7 seconds, how do I ...
312 views

### LTspice ideal diode simulation

I was trying to simulate a biased clipper circuit in LTspice, and came across this issue. This is the schematic I used: And the plots of voltages across V2 and R1: Ideally, the output voltage should ...
• 53
199 views

### Laplace of energy sources

What's the Laplace transform of an independent DC voltage or a current source? I came across this while reading transients from a book. While solving a first order circuit in Laplace domain, it took ...
68 views

### Transient and Surge Protection

It seems that when choosing ESD/TVS diodes, MOVS and GDTs that while their clamping voltage is rated in Volts, their protection is rated in Watts or Joules. For example, the LittleFuse SMCJ250CA is ...
• 49
1 vote
253 views

### Reverse voltage spike protection on high-side of a (coiled) relay without flyback diode

I have a microcontroller interfacing with a normally-open automotive relay on the high-side, through a P-MOSFET. When the microcontroller closes the P-MOSFET's Source & Drain (by sending LOW ...
• 113
152 views

### Validity of small signal model during transient state

In most of the books it looks like small signal is used as a steady state analysis, for example a capacitor is modelled as: $$Xc=\frac{1}{j \omega C}$$ Which clearly indicates a steady state analysis. ...
• 1,124
1 vote
255 views

### How is constant on time control better than voltage mode control for transient response?

I am trying to understand the benefits of constant on time control (COT) over voltage or current mode control. In voltage mode control, during a load transient (increase in load) an aggressive control ...
• 2,155
60 views

145 views

### AC Transient analysis of an RL or RC circuit

When an AC input is applied, the inductor in initial condition (uncharged) does not act as an open circuit, even though the magnitude of instantaneous AC voltage constantly varies. Why is its behavior ...
71 views

### How to control the transient output current of a synchronous buck converter?

I am dealing with the following problem, I want to control the output current and voltage of a synchronous buck converter during the output load (resistor) step change. Suppose we set the output ...
• 11
27 views

### Window comparator with transient detection

I need some advice with over range circuitry I my design. In summary, I need to probe two nodes in my circuit and raise an alarm if any of them raises above approx. 2V peak (in both polarities). The ...
• 195