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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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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56 views

When to factor duty cycle into power consumption calculations?

This is probably a simple question for most of you. I am calculating the power consumption of a device. The load is driven using a square PWM signal. At what point do I factor in the duty cycle? For ...
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61 views

How to generate a double PWM with a microcontroller?

I need to light a LED during a sequence with a microcontroller. The sequence is as follows : I need to turn on/off the LED with a given frequency (PWM 1). It will be between 1 and 200 Hz. When the ...
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65 views

SG3525 PWM duty cycle problem

I'm struggling to increase duty cycle in the controller. I'm using SG3525 on control PCB. As can be seen below, R12,R22 and C12 components are selected for 58kHz frequency. However, I can't get duty ...
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56 views

Limiting the pulse width of a PWM by using voltage divider and a single power supply

I'm using a Tl494 PWM and I want to limit the pulse width from 0% to 80% of the signal as maximum. How can I achieve this using a SINGLE 5v reference supply (I know it can be achieved by using two ...
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42 views

Range of duty cycle ms to drive RC servo motor and transfer function

I am using the ball and beam control system from Acrome robotics and I would like to identify the transfer function of the RC servo motor which translates motion to the system. First of all, I have ...
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1answer
55 views

How can I make smaller steps with my servo?

I've got a Raspberry Pi with which I control a servo. The servo controlls the rudder in an autonomous boat I'm building. I'm using Golang and this gpio library to control the PWM. The input I get ...
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1answer
62 views

Problems with DRV103 PWM

I've been doing some work lately with the DRV103 IC by Texas Instruments (datasheet here, essentially it creates a PWM signal of variable duty cycle and frequency, preceded by an 'ON' signal of ...
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139 views

STM32 simultaneous PWM output with variable frequency and duty cycle

I've been designing a capacitor discharge welding machine for a while, So the working principle is when the button has been pushed, 3 output will initiate simultaneously which 2 of them is variable ...
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3answers
156 views

Relaxation oscillator, how to change the duty cycle

I have a Relaxation Oscillator here. What I'm trying to do is to change the duty cycle of ca 50% to 10%. What I thought of and tried to change R1 and C1 values so the time the capacitor loads and ...
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1answer
49 views

Spectral lines vs Envelope of PWM wave

On the wiki page of 'Duty Cycle' there is a nice animation that shows the frequency spectrum of PWM wave as its duty cycle is modulated from 0 to 100%. The animation shows the 'spectral lines' as ...
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81 views

PNP transistor interface is not switching PWM inputs with low duty cycles

The following transistor circuit section(using a PNP transistor BC557B) is inverting and buffering a 25kHz PWM pulse train coming from one of the Nano's PWM supported digital pins. The following is ...
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114 views

Current rating vs duty cycle

Is there a rough relationship between the current rating of a device, say a connector, and the duty cycle? For example, I assume a connector rated at a continuous 5 amps isn't necessarily going to be ...
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3answers
45 views

How to measure current in very low duty cycle circuit with DMM?

My circuit has 4Hz 50% duty cycle. How do I measure the average current using a DMM? I have a Fluke 87 DMM. It has an average setting but for 100 ms which less than one complete duty cycle. My ...
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50 views

Buck Converter MOSFET Output Voltage distorted (PWM)

The input to my buck converter MOSFET switch is a PWM signal with a certain duty cycle. However, upon observing the voltage waveform of the MOSFET, the voltage is a bit distorted. The input to ...
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1answer
65 views

SIMPLE digital control over 555 timer frequency and PWM?

I'm looking to create a sound generator with only simple ICs and components. I believe the 555 timer IC is a good candidate to be at the core of it, but I cannot for the life of me find out how best ...
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2answers
103 views

Thermal calculation in case of duty cycle for a mosfet

For a multiplex LED matrix, I am intending to use two ULN2803's as sink source for 16 times 20 mA per column (channel). However, maybe I will try a test with 100 mA LEDs (10% duty cycle). For that I ...
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1k views

STM32 PWM problem

Using a STM32F407 board. I want to generate a PWM signal. I have the following function: ...
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1answer
408 views

Adjusting duty cycle without affecting frequency of a VCO

I've looked around the internet for a simple voltage controlled oscillator that is able to produce various waveforms in phase with one another. I asked about it in this site and was directed to a dual ...
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1answer
69 views

Which Approach is Better to Drive Brushless DC Motor with PWM Duty Cycle

I'm doing a project that use brushless geared DC motor, the motor is connected to a moving platform. I will drive the motor with PWM, the motor then move the platform from -a degree to a degree ...
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1answer
76 views

High and Low times for 555 oscilator are inverted

I’m new to electrical engineering and this is my first time working with an oscillator. I'm trying to setup a 555 timer ic as an oscillator with a low time of 1s and a high time of 0.5s. I've been ...
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2answers
38 views

Run actuator at higher voltage and with lower dutycycles

I have an actuator which is rated at 12 VDC input voltage (0-15) with a maximum allowed duty cycle of 20%. The already existing voltage levels in my system are 5V and 22V, and since I am weight ...
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1answer
353 views

How to measure duty-cycle with Input Capture from STM32F103C8T6?

I'm trying to measure the duty-cycle of the 0-5V electrical PWM signal I have generated from the any source. How can I do this? Anyone can help me? IDE: Keil Microcontroller: STM32F103C8T6
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124 views

What is the physics behind width of the duty cycle in Arduino?

I was wondering if someone can tell me how Arduino changes the width of the duty cycle? How it produces an on-off pattern? I am looking for an explanation for modulation in this system.
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1answer
50 views

Determine MC34063AP Duty Cycle

A fuzzy area I want to clear up on the MC34063AP is Duty Cycle. In the MC34063AP datasheet, toff an ton are a result of 1 / f, which is obvious. toff is calculated by: 1 / f / ton / toff + 1 ton ...
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97 views

DC motor parameter identification using microcontroller

I've built a DC motor controller which measures the speed and current (not really sure yet about current values) of a permanent magnet DC motor. I plan to connect different PM DC motors. Is there a ...
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156 views

Optimal duty cycle in Forward converter?

So as far as I understand the Forward topology: The duty cycle set by the controller in CCM mode is constant assuming constant input voltage and constant output voltage. The duty cycle is independent ...
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4answers
3k views

Servo PWM: Why 20 ms period?

I'm working with ESC controllers which receive PWM signals that are very similar to those that control a standard Servo motor, i.e. a 50 Hz PWM signal (20 ms period) with duty cycle of 5-10% (1-2 ms ...
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1answer
274 views

Basic definition of duty cycle

Does the definition of duty cycle indicate only the percentage of time that the level is asserted? For example, if a 10 Hz square wave is de-asserted for 5 of those 10Hz cycles and asserted for 5 of ...
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3answers
579 views

how to make a square wave 1kHz circuit [duplicate]

i want to make a 5V oscillator that has a frequency of 1khz. it will basically go to 5V (HIGH) and then 0 V (low) in a frequency of 1khz with 50% duty cycle.
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186 views

Is it possible to generate different PWM Signals for same duty cycles(e.g. 50%)?

Let us expect we have a duty cycle of 50%. Is it possible to reach that duty cycle with different PWM Signals (waveform)? With different I mean variants in the number and lengths of the "active time". ...
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2answers
636 views

How to regulate PWM to control a boost converter

I am creating a simple boost converter following the classic circuit diagram just for learning purpose. The switch is a power transistor controlled by PWM output of an Arduino (with additional ...
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1answer
415 views

Defining contrast ratio and dimming ratio in a LED driver

I read in this article which analyze the contrast ratio achievable with switched mode LED driver system, that is defined as \$ \frac{1}{t_{on}} : 1 \$. Intuitively I can get that the minimum time ...
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51 views

Analysis of the full bridge bidirectional converter's buck mode operation?

This is the circuit I was trying to learn. Here is the equivalent of the buck mode operation: And following is the waveform in the buck mode of operation: My intention is to derive the output ...
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1answer
194 views

How can I add variable duty cycle PWM to a CircuitLab simulation within a question?

This is my first attempt to simulate a circuit in the time domain with CircuitLab. In order to ask a proper question about something similar driven with PWM, I'd like to add an adjustable duty cycle ...
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1answer
163 views

Control the duty cycle of my square oscillator

I Would like to know how i can control the duty cycle of my circuit. simulate this circuit – Schematic created using CircuitLab What is the best way to control the duty cycle ( from 1 to 99%) ...
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4answers
2k views

analog PWM signal

I am trying to get a PWM signal with adjustable duty cycle using only analog components, hence using a timer is not possible. Now I got one way of using it, using the triangle waveform and putting it ...
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1answer
1k views

Pulse generator with single op amp and diode

I want to design pulse generator with specific period and duty cycle. I found a pulse generator with single op amp and diode. I couldn't find information about how to calculate period and duty cycle. ...
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1answer
3k views

Driving servo motor with PWM signal

I want to drive servo motor with PWM signal.Servo motor rotation angle changes with the ratio of the duty cycle.Generally , servo motor rotation angle according to PWM can be seen in figure below. ...
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2answers
397 views

The logic schematic which can change the duty cycle of input

Is there a logic schematic can change the duty cycle of input ? I mean if input is a square wave with duty cycle is equal to 50%,and the output is also a square wave but its duty cycle become lower or ...
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2answers
3k views

independent control of frequency and duty cycle in 555 timer (formulas)

I want to control frequency and duty cycle of output pulse of 555 timer. I searched and find this schematic in a post in SOV but I don't know how calculate frequency and duty cycle in the circuit. ...
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2answers
2k views

how do I control duty cycle of a MOSFET using PI controller

I have designed a buck boost converter, how can I use a PI controller which will automatically change the duty cycle of the mosfet as per my desired output voltage or current? I have been fidgeting ...
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1answer
147 views

'Subcircuit is undefined' when designing PWM with TL493 in PSPICE

I am trying to design a PWM for my converter using TL493 in Pspice and i am getting an error. ERROR(ORPSIM-15108): Subcircuit model591_tl493 used by X_U1 is undefined i am a beginner to both ...
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2answers
2k views

Do 100% duty cycle buck converters have no voltage drop?

I am currently designing a circuit which should be able to take 12-28V DC power in and output 12V DC @ 1.5A. The question is: is this possible with a 100% duty cycle buck converter (like TPS54302)? ...
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1answer
71 views

Duty Cycle Demodulation Distortion Correction

I'm trying to come up with a system which will reliably convert an arbitrary input to a PWM signal, and then back again. The comparison signal is a 50kHz sine wave, and the result is fed through a ...
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5answers
5k views

Is there a way to sweep duty cycle over time in LTspice

I can sweep the frequency in time by using modulate, but I couldn't find any example on creating a varying duty cycle or a duty cycle is swept from zero to 100% at a given frequency f in a time ...
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1answer
248 views

Average voltage (pwm regulated) out of motor voltage range?

My DC brushed motor is rated 4.5V-15V. My application requires the motor to spin with different speeds so I am using PWM to regulated the it. I will be supplying the motor with a 12V battery and using ...
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4answers
1k views

100% Duty Cycle PWM

I recently had to build a filter to go from PWM to 0-5Vcc, and it got me thinking... At 100% duty cycle, the PWM used was 100% 5V output, DC voltage... If i used this PWM to, for example, switch a ...
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4k views

DC motor speed vs PWM duty cycle

I understand there have been quite a few posts asking about the DC motor speed vs PWM duty cycle issues. However, I found those questions different from what I want to ask, so I have to ask this topic ...
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1answer
2k views

555 - Adjusting frequency without affecting duty cycle

This seems to be some easy thing someone figured out already, but here I am after an hour of searching - and fearfully asking the question. My aim is to build a relatively simple 555 circuit using as ...