Questions tagged [duty-cycle]

Duty Cycle is the ratio between duration of a pulse and the entire period of a (repeating) square wave, expressed in %.

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PWM signal generator circuit does not work in real life

I designed the motor soft start circuit in the figure below. I ran the circuit in simulation programs, but when I tried it on a breadboard in real life, I could not get a PWM signal. When I examined ...
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While using this library (FastPwmPin.h) output frequency is coming exactly but not duty ratio?

I am doing a simple power supply for that I need PWM signal to turn ON and OFF the MOSFET. For this I am using arduino UNO for PWM signal generation. So I used a library called FastPwmPin.h to ...
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Adressing timing issues on a pipelined logic circuit

Original title: How to modify the duty cycle of crystal oscillator? I have a 25.175 MHz crystal oscillator with a duty cycle of 50%. How can I reduce the waveform to a 25% duty cycle? It doesn't have ...
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Making duty cycle with CTC mode in AVR without using interrupt

I am writing a program to make an output with a 30% duty cycle and a frequency of 3 kHz using an ATmega32 microcontroller. My controller's frequency is 8 MHz and I am going to decrease it to 1 MHz by ...
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Increase minimum PWM duty cycle for high resolution PWM

I'm working on a project involving driving LEDs at a 20kHz PWM frequency with 1024 bit resolution. I've calculated that the minimum pulse time, (1/frequency)/resolution, would result in a minimum ...
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I have modified a simple blocking oscillator. How can the frequency, duty cycle or efficiency be otherwise increased?

In this schematic is a simple blocking oscillator. Note that this won't simulate, as Circuit Lab does not have the type of toroid needed, but if you breadboard or prototype this circuit it will work ...
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precise 50 Hz oscillator [closed]

I need an astable multi-vibrator at exactly 50 or 100 Hz with exactly 50% duty cycle. using circuits like 555 can't give me that with the common well-known values of components R and C , let alone the ...
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Precise square wave generator 32768 Hz

I need to create a circuit to generate a square wave with 50% duty at 32768 Hz +/- 5 Hz. The output of the circuit will drive an NPN transistor ( 0.2 A , 24VDC ). The cost of the component is not a ...
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How can an instruction be fetched every cycle?

From what I understand, in a pipelined CPU, every stage takes 1 cycle. But instructions are fetched from memory which takes up to ~150 cycles. The CPU fetches most instructions from the L1-cache, but ...
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Varying duty cycle of an square signal using comparator

Recently i've been tinkering with the interrupter of my solid state tesla coil and the circuit that utilizes two ne555 timer ic,one in astable mode and another one modulating via pin 5 of the first ...
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Can I reduce flyback transformer into a single inductance to calculate the duty cycle of the MOSFET?

I am trying to calculate the duty cycle of the MOSFET in a flyback topology SMPS. From the selected converter's datasheet, I am given the equation: Since I am using a flyback topology, what is my L ...
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Laser Power Control Using Duty Cycle

I have a Coherent Cx-10 CO2 laser that I want to use for laser heating of very small samples at high pressure, so I need to accurately control the laser power. I also have a pulse width modulated ...
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Can't figure out this PMDC motor model

I was going through a series of experiments on PMDC motor where I found out the following block diagram representing the system: I'm new to this field and I'm trying to get a little ahead of my ...
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Output voltage from L298N

Is it normal to have a higher output voltage than expected from an L298N driver? I have read that there are voltage drops and it is usual to have lower output voltages, not higher ones. If it is a PWM ...
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What Happens when PWM Period register and Compare register is also loaded with same value

Consider, PWM engine based on timers, PWM period register is loaded with 0x3FF (10bit, specifies the period of pwm frequency) and compare register( to vary the duty cycle , when timer count = cmp ...
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555 Timer duty cycle changing formula

I am making a PWM motor speed controller. I used the Astable mode thinking it would work; it did not. Using an oscilloscope I noticed that I am only changing the frequency not the duty cycle by ...
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Factoring duty cycle into battery design, give battery life

I have been given the following scenario: LED output: • assume 200 communication codes per 24hrs, and that each of those LED code words take 20msec of processor time to communicate BLE: • connect ...
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Error in compensator for buck

I'm trying to put my ZVS buck converter (DCM) in closed loop. I ran some simulations on MATLAB, and figured that just multiplying the transfer function of the open loop buck by 0.5 gives acceptable ...
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How to find the best settings for Cyclic voltametery test?

I am trying to conduct a CV TEST (Cyclic Voltammetry). However, I am unable to get the current peaks on my plot. I tried different ranges of Voltage at different scan rates. However, I could not ...
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How do you choose a PWM Frequency to drive a DC motor? [duplicate]

I can clock the PWM to drive motors at most any reasonable frequency, but is there a "best" PWM frequency for motor control? What must be considered when choosing a PWM Hz? Is there a most ...
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How to calculate duty cycle of a servo motor?

I have this servo motor and in its specifications only speed and torque is given: ...
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TL494 duty cycle adjustment

I'm building a simple pulse generator with a TL494 in single ended configuration. My plan is to set the frequency between 20Hz to 1kHz and duty cycle between 0% to 45%. I will adjust that with a ...
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Stepper Driver pulses control (with Arduino)

I intend to control the speed of a stepper motor thanks to a driver connected to Arduino (Mega). Basically the driver has, among others, 2 pins, PUL+ (Vcc) and PUL- (GND, common cathode), and each ...
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Boost converter depending on load

TL;DR: Output voltage of boost converter depends on load. I assume because the load is altering the voltage between the base of the boost transistor and ground, thus altering the duty cycle. No idea ...
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PWM signal duty cycle

I am using an Arduino UNO R3 to generate a PWM signal, the user sets the duty cycle using the serial monitor. The Arduino output signal is correct, but when the signal is connected to the input of the ...
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Is there a mathematical representation that represents the output voltage of a buck or boost converter in discontinuous mode?

Recently I have learned that in buck or boost converters, the output voltage depends only on the duty cycle and input voltage in continuous conduction mode or when current is continuous. However, in ...
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Why is the duty cycle much wider than it should be? PIC32MZ & PWM

I'm working with the PIC32MZ2048EFM100 and XC32. I'm using some outputs as PWM signal generators. There are frequencies for which the pwm works fine, but not for others. For example to get 24.4 kHz, I ...
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Duty cycle calculation

I am trying to solve a numerical where the Speed of a DC motor operating at 15V was measured to be 2000 rad/sec. Now a PWM signal is applied to the same motor to get a speed of 400 rad/sec. If the ...
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2 answers
351 views

PWM output vs Digital output

Could I use a PWM output as a digital output? For example to act like an on-off signal by varying the duty cycle between 0 and 100%. Does it involve any difference in power consumption?
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I'd like to know whether my attempt to increase duty cycle will work

I've been looking for a solution to make an astable multivibrator give me a 90% duty cycle or a duty cycle above 50%. This is what I came up with. I have very limited resources and means of testing, ...
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361 views

How to make a pulse source with a changing duty cycle in LT spice?

I have a power electronic inverter, and I want to make the duty cycle of the PWM dependent on the ratio of "vout/vin", where vout is an AC power source. Unfortunately, setting .param D= IF(V(...
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Duty cycle of 555 timer

I am trying to understand the exact working of this circuit, I have been told that this circuit provides a duty cycle of 50% from my previous questions, the same which I successfully verified in ...
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Lower duty cycle less efficient?

Assume you have a DC voltage V, ideal switch (no switching losses) operating at some frequency f and duty cycle ...
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Is it possible to measure pwm load current using opamp based high side current sensing?

I am referring this app note, hope to use as unidirectional current sensing for a PWM load PWM load - load is a resistor, PWM signal - 100Hz, 150V. Load current 18mA Duty 5% (PWM resolution 8 bit) ...
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How can I cycle through 4 LEDs with Timer Off Function (TOF)?

I have 4 LEDs that need to be turned on and off sequentially and cyclically. This is my code from code warrior: ...
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Buck converters duty cycle

From this article: Power Tips: Power converter topology... they say that: Moreover, buck-converter duty cycles become extremely small in high-voltage AC/DC conversion. For a 440VAC to 15VDC ...
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Dutycycle DCDC control

I will start with that, i already ask for this question in other topic but i didn't have any anwser about my question link. Please don't go too far in explaning difficult thing not realated with my ...
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How to generate PWM with different frequencies and duty cycles?

I am going to use TMS320F28027 for PWM generation. I have to generate 5 different frequencies of PWM with different duty cycles at a same time. How it could be implemented? Can I use a single PWM ...
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Controlling Proportional valve with NPN transistor (TIP 122) using PWM

We are working to control the proportional solenoid valve (9C, 2W) (VSO by parker, datasheet) by changing the voltage across it. For this we are using PWM from the controller, thus changing the ...
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555 timer as a voltage controlled oscillator, duty cycle query

I`m trying to create a square wave generator using a 555 timer but i noticed that due to the pulse width modulation as i vary the control voltage, the duty cycle changes so i was wondering if there is ...
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Maximum AND minimum duty cycle in SPICE converter simulation

I am modeling a Push-Pull Converter in LTSpice and implemented this for a simple voltage feedback PWM control. This works great and I have added a bit on the end that allows for a maximum duty cycle ...
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Calculate duty cycle of flyback converter

MY ATTEMPT I found a formula for the DC transfer function for the flyback converter: $$\frac{V_{out}}{V_{in}}=\frac{N_s}{N_p}\cdot \frac{D}{1-D} $$where \$ \frac{N_s}{N_p} \$ must be the ratio between ...
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Using 555 timer with soil moisture sensor

I am using an IRROMETER sensor for soil moisture measurement. This sensor requires AC excitation, so I found an interfacing module for it from online. This is the circuit recommended by them: The ...
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How to handle duty cycle below deadtime in 2- and 3-level inverters

When programming a pwm for a 2-lvl inverter what would be the suggested strategy for a duty cycle close to 0% or 100%, meaning when I cannot guarantee for dead time. What would cause less distortion ...
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I need to vary the duty cycle between 50% and 70% of a PWM signal

So I used a comparator to compare a sawtooth signal and a reference voltage and I obtained the PWM signal at the output of the comparator. My question is what formula can I use to vary the duty cycle ...
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What is a best way to get a 25% duty cycle square wave (5 V, 1 MHz) on a board?

I am trying to get two off-phase 25% duty cycle square waves(1MHz) to control a full bridge circuit. Update:Sorry for the confusion here, what I mean was to have 2 square wave signals, and introduce ...
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Output Voltage of a Current Mode Controlled Flyback Converter

I'm trying to use the NCP1014 (65kHz) to make a flyback converter. I'm using coilcraft's transformer B0570-BL which is specifically designed for the NCP1014, with turns ratio 1:0.06 or 16.67:1. I ...
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20kg digital servo not working, probably because my frequency calculations are very wrong (raspberry pi)

summary I changed my servos for a more powerful one and cannot get it to work, I believe it is because I can't get the right duty cycle calculation in the code explanation I have a robotic arm that I ...
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Making PWM with analog input control in PIC18F4550

I am trying to program with the PIC18F4550 a PWM with which I can regulate the duty-cycle with a variable resistance. I attach my code to explain the problem I have. ...
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Drive signal (duty cycle) calculation for PI compensator

I am trying to simulate an inverter with 4 ideal switching devices in LTSpice. I have the compensator working, however I don't the correct equation in terms of calculating the duty cycle. What I ...
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