# Questions tagged [time-constant]

A parameter which quantifies the time a circuit takes to reach one value from another (i.e. a step response).

103 questions
Filter by
Sorted by
Tagged with
57 views

### Time Constant Equalizer [closed]

I found a device made decades ago and long forgotten now. It was a simple device that compensated for the non-linearities produced by a moving magnet cartridge for audio. I am not a scientist just an ...
72 views

### What's the physical significance of increasing R and decreasing C in a parallel RC circuit?

I'm studying a chemical process and am representing it with a parallel RC circuit. Through experiments, I found that as time progresses, the value of R increases and the value of C decreases, while ...
151 views

### Finding Deboo's integrator time constant and transfer function

I tried to determine the transfer function and time constant of Deboo's non-inverting integrator. If I calculate with an ideal op-amp, then my calculation fails if the ratio of R2/R1 and R4/R3 is the ...
• 329
58 views

### How to calculate the time constant for an attenuation of specific frequencies in a Lock-in Amp?

I am new to the signal processing field, so I am studying what I can and trying to figure stuff out, but I have found one piece of information I really cannot find mentioned anywhere, yet seems very ...
49 views

### Where am I going wrong in voltage equation of Capacitor in $RC$ circuit?

Where am I going wrong in voltage equation of Capacitor in $RC$ circuit? An initially charged capacitor with voltage $V_0$ is connected in series with a Switch and a Resistor. I was able to derive ...
73 views

### RC circuit not working as intended

I am trying to plot the waveforms is following RC circuit and I am not getting the intended results: The first voltage controlled switch (S2) is on for 4 seconds, thus charging the cap for that time ...
73 views

### Find R value from capcitor discharge plot obtained using scope

I'm using an oscilloscope with probes that are specified to have to have an input resistance of 10Mohms, I apply 5 volts (using power supply) in parallel to my capacitor and use the scope in parallel ...
85 views

### How do we calculate the time constant of this circuit?

For the below circuit, C1 changes its voltage from +5V to 0V , whereas C2 changes from 0V to +5V. The time taken to reach 63% of total change ( usually ~RC) is around 636ms. But Iam not able to ...
• 3,134
67 views

### Whats the relation between RC time constant and the GBWP of an opamp?

If I'm not wrong, an opamp circuit's feedback resistor and capacitor dictates the response time of it. So in case we have the control over Rf and Cf we can set the response time. But in that case, ...
• 12.2k
119 views

### How to calculate the time constant of a simple cross coupled diff pair latch circuit

I have a circuit, which is given below. Now I want to find the time constant of the circuit, considering there are equal caps placed at node X and Y. For a small signal model I can easily find the ...
322 views

### Find needed capacitance of charged capacitor with constant power load

I would like to discuss the circuit depicted in the screenshot of a simulation in LTspice. Let's assume there is a capacitor charged to V0 = 25 V that is connected ...
• 752
670 views

347 views

### What is the perfect definition of time constant?

Is it the time when the current throught the inductor is 0.63 times of the maximum possible current through the inductor? Or is it the time when the current is 0.63 times of the maximum possible ...
186 views

### Based on EMI RL circuit.... time constant

How is the time constant for an LR circuit is determined in the case of charging, where one resistor is connected in parallel and another resistor is connected series to an inductor.
1k views

### Time constant vs Length of Pulse in RC circuit

Reading through "The Art of Electronics", I came to a statement where the writer states that the time constant (t) of RC circuit must be many times bigger than the Length of pulse you want ...
• 1,079
1 vote
746 views

### RTC circuit supercapacitor charge/discharge doubts

This is my current RTC circuit... Supercapacitor = DXJ-5R5V334U (ELNA)... DXJ-5R5V334U = 0.33F, 5.5V, ESR = 150 Ohms Resistor = 150 ohms 0603 100mW 1% If I consider only the resistor, I have a RC ...
• 657
58 views

### time constant of rc circuit

How to calculate time constant of this circuit. .. and how the time constant of C1 and C2 are related
1 vote
5k views

### Time constant of 2nd order system

Why there is no general definition of time constant for 2nd or higher order systems , while 1st order systems have a proper definition of time constant. is Time constant defined for every systems ...
• 1,184
97 views

### Some confusions on a basic CMOS multivibrator question

This is a previous exam question, so I do have a solution already, I am not trying to make you solve my homework etc. Few questions in my mind regarding this question above, There is not a given ...
• 2,106
31 views

### Capacitance modulation to maintain current-voltage (IV) character

The ideal capacitor DC analysis shows the time constant to be a function of the load resistance and capacitance. Since the load resistance will be constant during discharge, is there any research on ...
1 vote
890 views

### Time Constant of a tricky RC circuit

I'm trying to find the stored charge on capacitor1 at time $t$ So, I think I have to find the voltage on the capacitor first. In terms of Current, the total current $I(t)$ should be the sum of ...
• 11
98 views

• 551
835 views

### understanding the graphs of tau vs R in an RC circuit, and tau vs 1/r in an RL circuit

from my understanding, in a circuit like this one: in order to calculate tau, you can use the inductor's value divided by the resistor's value. as the resistance (or impedance, in A/C). As R changes ...