Pwm Definition and 76 Threads

Hi guys, I need to use the PWM output of a PIC microcontroller to switch a mosfet to drive a 9v brushed DC motor @ 115 mA. From what I've gathered, the mosfet should be logic level (fully on @ 3.33v since my Pic uses a 3.33v source). It needs to be able to handle...

Hi- This lab question has me stumped... Homework Statement Derive an equation describing the effect of the control voltage on the pules width for a 555 pulse width modulation circuit (monostable circuit). Homework Equations width = 1.1*R*C The Attempt at a Solution I took...

I need to find out how a certain pulse width modulation duty cycle is used in SMPS power supplies (specifically a boost converter). Also, how does the oscillation contribute to a voltage transformation? (step up) Any pointers to some articles are welcome

I am working on a 3D crane system, the system has three dc motors for y, x and z axis, and i control them with a PWM signal. i need to find the relationship between pwm and torque or torque and duty. could someone help me, thanks

Last year I built an electric car. I converted a 1966 MG to electric using 8 led acid batteries (96V bus), a DC motor coupled to the transmission, and a large motor controller. The vehicle was working fine. Top speeds of 55 mpg, but with many led acid vehicles, only a 20 miles range. The DC...

i am trying to design a switch that will output an active high if the width of the received PWM signal is greater then 1500 uS. if it is shorter then this time then it should output an active low. The frequency of this signal is 50 Hz. I designed a RC circuit with a cutoff frequency of 50...

Hi all, This is my first time making a somewhat complicated circuit, with the help of an online schematic. (http://www.dprg.org/tutorials/2005-11a/index.html ) My goal is to make a New Year's Eve ball-drop, which has a motorized controlled-release lit-up ball (on a separate power...

Hey all, I'm a junior in high school building an ROV for the MATE ROV competition with a amateur robotics team this year. For this year's competition, we've decided to control our bot via an Arduino Mega, and we're using PWM to potentiate the thrusters. As the person designated to electrical...

I would like to increase the maximum current that a PWM signal from a microcontroller can source/sink from +-25mA to +-500mA. The output should have the same peak-to-peak voltage (0 to 3.3V) and should not be inverted (i.e. follows the input). The PWM frequency is ~30kHz. I have looked...

Hi. I am working on a circuit to control a dc motor using a pwm signal. The problem is that the pwm source (a LabJack UE9 DAQ) doesn't send a ttl signal, but a 0-3.5 volt signal (3.5 peak to peak). The power transistor needs about 5 volts to open completely between source and drain. A...

Hello all. First off, I am a total newbie and need some help in getting my "project" up and running. Here goes, I'm trying to get a dolly (weighing around 50lbs. or so) to move at a fairly slow constant speed. I'm thinking my best option is to find a 12 volt DC motor along w/a speed control...

I need to know how can I increase the duty cycle of a pwm. Thank you very much :)

Hi, I am trying to build an inverter and i am using Tl494 for my PWM, i am getting the right frequency but am not getting the 50% duty cycle. Can anyone suggest me any ideas on how to adjust the duty cycle for Tl494 Thanks. Krishna

Hi I have a question to do with using PWM If for example I had a 1ohm load and a voltage supply of 4JC-1, I would get a power draw of 16JS-1, now if I had a duty cycle of say 50% I should get an average power output of 8JS-1. However if i thought of it as having an average current of 2CS-1 and...

Hi guys, i need help on my assignment. The problem i have is reading the output of this IC chip (UC3524). Apparently you can't just connect an oscilloscope to the output and get a reading. My teacher said something about using transistor? Here is the IC chip's schematic...

I recently encountered (not for the first time) a situation in which a PWM output from a microcontroller is sent to a MOSFET bridge that drives a motor (a very high current, inductive load). I started to wonder exactly WHY it is that the duty cycle of the PWM controls the motor speed. I know...

I've heard that one of the applications of PWM is to control the intensity of a light source (e.g. as in a dimmer). My question is, if you send a square wave voltage with a certain duty cycle to a lamp, it seems to me that it would have to be at a high enough frequency that humans wouldn't...

Hello everyone, First time posting here, thanks in advance to anyone who can help. I'm building an HHO generator, otherwise known as a water fuel cell, or high efficiency electrolyser. The concept is to separate water using a high voltage signal at resonance instead of current. What I...

Hi.. How to calculate the power rating of PWM pulse train? Reg, Sridhar

Can anyone please send me the simulink model of boost converter i couldnot find any in the MATLAB help tutorials... I didnot know how to give the pwm control in simulink..could anyone please send me the model..

Hi Everyone, I'm new here and I hope someone can help me with my project. I need to design a Space Vector PWM circuit block connected to my DS1102 PWM hardware block in Simulink. Anybody have any ideas? Here's what the dSPACE support people wrote: Here is some advice from hardware...

Hello All, I am working on making my own custom three-channel function generator with duty cycle adjust. I bought three of these electronics kit function generators (http://www.electronickits.com/kit/complete/meas/fg500k.htm) . I want to build a project box with three 555 timers wired up...

any body have a good design for a p.w.m that has a adjustable start current and ramp up time

Hey guys. Just trying to program a microchip. Trying to grasp the concept of PWM. I know that varying the duty cycle will vary the speed of my motors...but there are other registers that allow you to set the frequency of the PWM peripheral...NOw I'm getting confused...isn't the duty...

Hello, I am trying to create a PWM circuit but I need a couple controls with in it. I need to control frequency and pulse width (duty cycle)seperately with 2 pots. This is going to control a spring loaded electromagnet for oscillation. I need pulse width control because of the varying...

I am getting confused between duty cycle and frequency of a pwm. Isn't duty cycle related to frequency? Can someone explain? Thanks & regards