Pulse-width modulation, is varying the duty cycle of a rectangle wave, usually with a constant frequency.

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59 views

Help debugging this pwm controller

So I'm sitting here playing with this PWM controller. I've been playing with it for about 5 hours now. And so help me god, not even once have I gotten the output to work, in any way. I'm powering it ...
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1answer
46 views

How do I calculate the max pwm frequency my h-bridge can handle?

my configuration: H-bridge with 4 n-ch mosfets (IRF1405) with a gate capacitance of 5480pF and turn on delay time 13nS. I am ...
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2answers
44 views

Driving a transistor base with PWM

I'm in desperate need of help here! No matter what I try, I can't seem to get this working! I'm trying to drive a signal transistor with PWM on an AVR ATmega32. My PWM signal looks as it's supposed ...
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1answer
49 views

Practical issue with PIC PWM

I have written the following code to generate PWM and to change the duty cycle when a button is pressed. In simulations it works fine. However when actually implemented the circuit, the PWM starts ...
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1answer
32 views

Current Controlled Output Using PWM

I am looking to control a proportional valve with a PWM signal that will correlate into exact current amounts (for example a 25% duty cycle will output 200mA, and a 90% duty cycle will produce let's ...
0
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1answer
81 views

Netduino Interrupts Affected By PWM - Diagnosis of Issue

I've got a funny problem with interrupts and PWM signals that's causing false interrupts to trigger. What exactly is happening is that I'm using a hardware debounced quadrature rotary encoder. The ...
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1answer
39 views

Why does my PWM Arduino loop not working as intended?

I have a Arduino sketch I am trying to use to control a DC motor using PWM. It seems it it just running the motor as if I the PWM was set to 255 (100%). I intend for my sketch to start the motor ...
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2answers
92 views

PWM generation PIC16F628A

I have followed the instructions in the data sheet and tried to generate PWM signal using PIC16F628A. However it seems to be not generating any output. My code is shown below. Any help appreciated ...
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0answers
54 views

Do I need to use a programmable oscillator?

I can produce pwm signals with my mcu and I am intended to use this signal to feed another MCU's external clock input. But my output pwm signal voltage is 5V and I need peak to peak 2.5V signal and it ...
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1answer
58 views

designing LC filter for linearizing PWM output

I have designed an h-bridge to run a TEC element. The circuit outputs output current is 4A output voltage is 4V Runs on PWM with frequency 5kHz Load resistance is 75Ω I wanted to linearize the ...
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1answer
56 views

Generating PWM from rectified sine wave using 555

I want to generate a PWM signal from a rectified sinus wave similar to the image below using 555 timer IC. I have designed the circuit below for this. I want to get a duty cycle of 80% at the ...
0
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0answers
69 views

How to use a crystal oscillator

I am trying to use a crystal oscillator as a clock signal for the PWMCLK input of a LED driver chip (TC62D723FNG) I have a FOX 1813-0245 8926 25.00000 MHz crystal oscillator I picked up at a local ...
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1answer
73 views

Long wire PWMed LED lights

so I plan to build a house (at some point in future) and I'd like to implement some sort of home automation. Now one of the things I'd like to have is PWMed lighting. Most of the lights would be 12V ...
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1answer
88 views

How does the PWM from MCU get translated into a output voltage as in Power Electronics [closed]

Background: I am preparing for a full-time employment starting in May. I am coming from a computer engineering background so I only have some working knowledge regarding EE. The job duty is Firmware ...
3
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3answers
489 views

What determines how much current can flow through a 2N2222 A?

I've been fiddling around with a brushed DC motor, a 2N2222 and an arduino's PWM to get different speeds out of my motor. Now, based on a video tutorial I watched on youtube, It was recommended to put ...
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2answers
113 views

Automotive PWM fan control using Arduino

I did a search here, but found zero results. Please keep in mind that I have very little electronics knowledge, but I am very willing to learn. I would like to be able to control an automotive ...
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1answer
46 views

Does low frequency PWM create reactive power in a transformer?

I got a 350VA transformer (230V~/24V~) which is directly connected to a heating unit at it's 24 V ends. The 230V end of the transformer are connected to 230 V~ mains over a solid state relay (SSR). ...
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2answers
68 views

BLDC Motor Commutation Based Speed Control

I am working on a project which has a motor to drive a gyroscope (it has quite a bit of mass, and we want it to run at 60k RPM or more). The motor we built has very low inductance. We started using ...
2
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3answers
72 views

Audio PWM DAC filtering

I have an msp430 synth project and can't decide on the output: I get an 8 bit ~45kHz PWM output out of the chip which I'd like to use as an audio signal, but I am unsure whether I can just stick ...
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0answers
46 views

Controlling a TLC5927 LED Driver

I am trying to control TLC5927, with no success. I have read the whole datasheet, but I still can't figure it out. I tried to simulate it, with no success too. Can someone draw me a timing diagram ...
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1answer
82 views

Motor/driver for smoothest and most constant speed

Which type of motor/controller can maintain the smoothest and most constant speed in the range 300 - 1000 rpm with minimal vibration? ie: low cogging torque, etc. I have an application in mind which ...
0
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1answer
51 views

Is three-stage lead acid battery charging possible with PWM solar charger?

I have studied lead acid battery charging methods from the website http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery. In which they mention three stages of charging: My ...
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0answers
72 views

Keeping current constant during PWM dimming of a LED string

simulate this circuit – Schematic created using CircuitLab I'm looking for a good control method for PWM dimming a string of LEDs and keeping the current through the LEDs at a constant ...
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1answer
61 views

Control 12V MOSFET with 5V, with PMW pass-through?

I am new to electronics, and still tying to fully wrap my head around MOSFETs. I have a few questions about controlling a 12v MOSFET using only 5v to the gate, and an incredibly small amount of ...
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1answer
158 views

What are the advantages of an ESC over a PWM?

I'm building an octocopter, and can't quite understand what an ESC (electronic speed controller) is used for. A brushless outrunner motor has three cables. Is there one common ground, one power supply ...
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96 views

STM32 Pwm Input Mode Problem

I am using Stm32f103 mcu and using TIM4 CH2 Pwm Input mode. My problem is, the data that I want to capture has minimum 0.75 us waweforms its about 250KHz frequency. I see the ccr1 and ccr2 values ...
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1answer
94 views

Safely driving a SG90 servo with AVR PWM

I've read that servos tend to draw anywhere from 10mA to 200mA. Is there a standard configuration to drive servos using MCUs without directly connecting them to the output pins of the controller? Or ...
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4answers
116 views

Is PWM bound to a certain voltage?

I have been working mostly with 5V rated MCU but I am venturing into the world of 3.3V rated MCU's. That should not effect PWM,right? (PWM is bound to time, not voltage as I understand it) Any ...
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1answer
58 views

PC driven PWM for 96 Channel Motor Controller [closed]

I need to build a USB motor controller that can simultaneously manipulate speed and direction of 48 12Volt 15Amp brushed DC motors while having full support for up to 96 motors. This controller will ...
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2answers
145 views

Circuit to dim 40A/12V LED chain with PWM (Arduino output)

We have about 170 feet of LEDs (12VDC, 2.88W/foot) wired up in one chain. Currently they are driven by two switching power supplies (12V/27A). We'd like to control the whole chunk of them together, ...
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0answers
101 views

Control 12v motor with 5v PWM

I have 5v PWM (555 generated) and I want to control speed of a motor using it. The problem is my motor is 12v and by diving it with a 5v PWM I can't reach full speed of a 12v motor. my pwm generator ...
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3answers
66 views

Switching between several high power DC devices?

I would like to control several high power DC devices (12V DC LEDs). From a tutorial, I found that I can control these using a 3.3V PWM input and a MOSFET. From what I understand, the MOSFET only ...
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1answer
72 views

PWM with programmable Dead Time

I need to make a circuit that generates a PWM signal for a motor. The motor has 2 inputs - P and Q. They are the inverse of each ...
1
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1answer
126 views

Generating simple alert tone MCU project

A receiver part of my project should activate a light tor few seconds but they decided to add an alert tone which will be played on the PA sys of a building. I think input is 8 ohm imp PA. I was ...
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2answers
112 views

Why is OCR1B values are not stored?

I have following program to control two servo motors: ...
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2answers
80 views

Increasing the PWM voltage level from 1.8V to 3.3V

I need PWM pulses of 3.3V, and my micro-controller is giving 1.8V PWM signals. I have a voltage source of 3.3V. One way I am thinking is to use two cascaded inverters(like NOT-GATE) using MOSFETs. Is ...
2
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2answers
143 views

Arduino turning a knob left and right with Digital PWM [closed]

I am trying to find a way in order to turn an car amp's bass level knob left and right using an Arduino's digital PWM pin. I am thinking that a stepper motor would be the correct motor to use in order ...
0
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0answers
63 views

A4973 DC motor driver design considerations

I'm dealing with a motor driver circuit connected to a microcontroller (ATmega328). The load is a brush DC motor running at 12V nominal voltage. I need to detect when the motor is stall and for this ...
2
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4answers
164 views

Convert a PWM to analogue with double the voltage range?

I have a PWM output (0-5v) that I need to convert to an analogue voltage. Simple = RC filter. However, the voltage range from that analogue voltage needs to be twice that of the input voltage, and I'm ...
0
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1answer
68 views

How to store OCR1A value in ATmega16

I am working on a robotics project. Using timers in ATmega16, I am controlling servo motors. By incrementing the value of OCR1A I am manipulating the servo motor. After getting the desired position of ...
3
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3answers
147 views

Motor Control with PMW or RPM on heavy robot

I'm going to try to explain my problem as clearly as I can. I have been building a robot that has four wheels, 2 motors and 2 free wheels. Its a differential drive system. ...
0
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2answers
114 views

Blocking wait for pin change on a LPC1114 microcontroller

I need to synchronize the rising edge of a PWM with another signal pulse's falling edge on a LPC1114FN28 (trying to drive a TCD1304DG), but am failing to achieve this so far. I have tried the ...
4
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2answers
265 views

LEDs, PWM and Max Current

LEDs typically specify Peak Current as something like 100mA @ duty cycle = 10%, and a "Test Condition" (I_F, i.e. Continuous Current) current of, for example, 20mA. That's a 2-dimensional constraint ...
0
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1answer
114 views

driving 4 RGB LEDs with PWM using MSP430

I have a project in which I must drive 4 RGB LEDs using PWM directly from the MSP430. They are separated in two groups of 2 LEDs (1 PWM connection controls one color element of two LEDs) which means I ...
3
votes
2answers
109 views

Pulse-width modulation: how to set the duty cycle using two variable sources?

For a hobby project, I am trying to build an electrical circuit in which the brightness of two LEDs can be determined using two sensors: one for light (an LDR), and one for sound (a microphone, ...
0
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3answers
95 views

Can pwm pulse damage High Side Solid State relay IC ,driving Bulbs as load

I am driving a 12V, 10W Bulb and 12V, 5W Bulb (parallel connected) on one channel of high side driver solid state relay IC. For dimming effect, Bulbs are driven by PWM (Intial 3msec) then continuously ...
2
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2answers
190 views

Is there such thing as a PWM Transistor?

I have a 7-channel RC receiver that outputs PWM at 5V. One of the channels is controlled by a simple switch (on/off) on the transmitter. I'd like to use this switch to control a 24V device. The ...
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1answer
106 views

How to digitally “amplitude modulate” an LED

I am wanting to do some open-air LED communication experiments. I have a receiver that detects Amplitude Modulated light signals, and then converts that into sound. Currently, I hook up a series ...
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1answer
253 views

50/60Hz inverter output inductor design

Given a SMPS PWM inverter (for example an UPS) supplying voltage/current at 50/60Hz, how do you design an output inductor? I don't mean how you compute its value in uH/mH nor its current rating in A. ...
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0answers
15 views

about conversion of h-bridge [duplicate]

I want to know whether h-bridge could convert pwm to ac signal If we give 5v pwm signal to input of h-bridge how much voltage of ac signal will it produce.If possible explain clearly please