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

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1answer
32 views

Are there reasons besides audible noise to run a VFD at a higher carrier frequency?

VFDs - variable frequency (motor) drives - output a pulse-width-modulated carrier approximating a sine wave. The carrier frequency is typically variable. I've seen numbers as low as 1 kHz, and as high ...
-3
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2answers
37 views

Can a PWM fan be turned on and off with the control pin voltage?

Can a PWM fan be turned on and off through the control pin? Or can it only adjust speed? Is it just a fet that turns the 12V on and off?
0
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0answers
37 views

How dimension a LC filter to pwm signal [duplicate]

Hello, as you can see in shecmatic , I am creating a PWM signal by comparing a sine wave (50Hz) and a triangular wave (10kHz) which is within the block "PWM(10khz).... in ordem to control a full ...
0
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0answers
26 views

Arduino Mega ADC error when using PWM

I am building a temperature controller, where I read 16 ADC inputs (thermocouple amplifiers), and at the same time I am using 6 PWM outputs (at 10 Hz). When I am only reading the ADC values, I have ...
1
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1answer
66 views

Using Dither to achieve finer PWM resolution

In practical industrial applications (regardless of any particular industry), is there any use for a dither module that goes along with a PWM module considering HRPWM's are available. With my limited ...
1
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2answers
73 views

PWM frequency and LC filter

I'm new here, I have some fairly basic doubt. I am creating a PWM signal in MatLab by comparing a sine wave (50Hz) and a triangular wave (2kHz) .... So what is the PWM frequency will output? After ...
0
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2answers
43 views

Servo - PWM Resolution

I'm trying to create a servo drive function on an ATMEL microcontroller without using the built in PWM functions. Basically just with the ISR timer. My question is... what is the general resolution ...
-6
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2answers
122 views

PWM ~100mA LED's [on hold]

If someone knows of a prototyping solution for driving several LED's at >75mA I'd be grateful. I've taken 8 LED's out of an existing product. They appear to expect 70mA to 100mA for max brightness. ...
0
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1answer
136 views

pulse width modulation

I need help on number one of this practice assignment. I barely learned about this so it is kind of hard me to understand it right now. So any advice or help is appreciated. I want to determine the ...
1
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1answer
63 views

pseudo analog voltage using PWM

I am just learning Pulse with modulation technique. Is There any way to create a pseudo analog voltage using PWM from the digital output of ATmega16? How can it be done?
0
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0answers
41 views

Pulse Width Modulation (Fast PWM) in Microcontroller

I am learning Pulse width modulation. If I want to to generate a 2.5kHz signal having an average voltage of 3.3V using ATmega32 FAST PWM mode (WGM=1110), What will be the value of TOP(ICR1) and ...
0
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2answers
37 views

Inverter PWM frequency

I am making a modified sine wave inverter. The PWM wave is generated, switched using transistors, and then passed through a transformer. What is the PWM frequency required to generate a modified sine ...
0
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1answer
58 views

How to convert Clock signal to PWM signal?

Let's say i have a clock signal which i control its frequency making it going from 10Hz to 1000Hz. And i want to convert this to PWM signal, so that 10Hz gives 0% duty cycle and 1000Hz gives 100% ...
1
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3answers
114 views

What are the essential properties of a PWM signal that can be captured with an oscilloscope? [closed]

My question is regarding general guidelines when it comes to using oscilloscope captures in a professional-grade report to be presented to people working with signal processing, embedded systems, etc. ...
0
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0answers
31 views

How does a virtual DC bus provide negative dc voltage in transformer less inverters?

How does the topology (1st pic) eliminate Common mode current found in PV panels connected to grid without isolation transformers?
0
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1answer
70 views

Multiple TLC5940s on PCB “dropping out” when many outputs turned on

I've designed a PCB to connect 12 TLC5940s to an 8x8x8 RGB LED cube through 3 64-pin headers, which I will include screenshots of below. I have a separate board for controlling the anodes for ...
0
votes
1answer
48 views

how do i power a 12 v motor forward and reverse, using pulse wave modulation on reverse only?

I am trying to build a device which uses a 6-12 v 8 amp dc motor controlled by a 2 channel rf relay, and powered by a 12 v battery. i need the motor to run forward and reverse, but in reverse i need ...
1
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1answer
57 views

Capture/Compare/PWM

The PIC 18FXX2 microcontroller has a Capture/Compare/PWM unit. I understand what capture and PWM are used for. Capture can be used to time the duration of an event. PWM is of course used to generate ...
0
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1answer
55 views

Not sufficient brightness from Constant Current LED drive to 3W mini LED, with Arduino Nano

Now, after read my 6 thread tip, no solution clearly given, so I go ahead to my problem. When I power on my 4 LEDs gave fast full flash brightness for 3-4 seconds. That's a sign that all ...
0
votes
2answers
71 views

Simple PC fan controller PWM discrete components

Recently I switched some case fans in my pc to find the horror that the new ones were even louder than the old ones. After some quick checks just by eyeing and monitoring on my pc I can confirm the ...
0
votes
1answer
110 views

Get rid of back emf in motors

I am controlling motor speed by using PIC16F877A and L298, but motors give Back EMF which can burn the microcontroller. To avoid back emf, I have 3 options: Diode. Darlington pair. Optocoupler. ...
0
votes
1answer
42 views

Hacking an RC car controller to implement a joystick (PWM)

My RC car controller (transmitter) has only 4 buttons (left wheel forward /backward, same for right) I want to implement a joystick using Arduino. The Arduino will use PWM on the transmitter ...
0
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5answers
126 views

Driving a DC Motor without diodes

As you know, H-bridge circuits are used in order to control DC motors. Switches S1-S4 are closed to turn the motor in one direction, S2-S3 are closed for another. But at the time of changing motor ...
2
votes
2answers
51 views

PLD, FPGA or microcontroller for PWM decode?

I need to handle PWM output from a single channel of an R/C receiver. I want to count the width of the pulse roughly in 4ms increments, and based on different widths take action by switching LEDs ...
1
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4answers
135 views

High speed (>30KHz) 10-bit PWM generator

I'm looking for a way to generate a high speed PWM signal into a high impedance input gate driver IC. This would be used to replace a lab bench waveform generator. Preferably I would use something ...
4
votes
3answers
125 views

How to measure temperature of a syrofoam cutter hot wire?

I would like to create a hot wire foam cutter device. The wire material is nichrome, diameter 0.9mm, resistance is about 1.7 Ohm/meter. For best cutting results, I would like to control the ...
0
votes
1answer
55 views

Controlling servo: how to determine the angle and needed pulse-width?

I'm kind of new when it comes to using servo's with an Raspberry Pi. Although I do have some experience, I'd like to understand things a bit better. Therefore I would like to share some questions with ...
0
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1answer
63 views

Attiny85 PWM Not Working

A am new to AVR programming. I have an Attiny85 and an LED hooked up to pin 5 on the chip (PB0). My goal is to get the LED to fade on, then turn off and repeat. When I give power to the chip the LED ...
0
votes
1answer
88 views

Automatic switching of a constant current circuit

I'm running 14 ~3W (700mA) LEDs in series on a constant current LED Driver that handles between 36-65V output. The driver runs the LEDs at 600mA. The heatsinks I've attached are pretty small, and if ...
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vote
2answers
94 views

Power MOSFET or Relay

I want to operate a 12V automotive fan with a 3.3V uC signal. The (37-year-old) centrifugal fan draws 3.2A for about 100ms at startup and then a steady 1.2A while running for a maximum of 30 minutes. ...
0
votes
3answers
132 views

Transformer works on PWM at 50Hz?

I have an ardunio setup which is giving me output of 5V and 1A at 50Hz with pulse width modulation. I want to use this as input to the step up transformer and generate output of 60V. considering ...
0
votes
2answers
51 views

Timer0 and Timer2 configuration on atmega1280

I want to setup Timer0 and Timer2 to control the intensity of the LED (L) on the Arduino Atmega1280. The frequency has to be 10khz and the duty cycle will be controlled by a switch or using serial ...
1
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1answer
65 views

Voltage Mode Control of a DC-DC Buck converter

My previous question was about a hysteretic-style buck converter: Buck Converter Control Scheme- Why isn't just a comparator not enough? By what I gather from previous answers, a ...
0
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3answers
73 views

Mosfet is getting hot under 3v drive

I have a Arduino controlled RGB strip, which uses PWM to control the brightness of each colour. I have been using an Arduino UNO to do this but I have have just upgraded to a Photon by particle. ...
1
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3answers
49 views

Power Supply Selection for PWM Controled Landscape Lighting

I'm planning to build a multi-zone outdoor lighting system, controlled by an Arduino. This will be a 12v DC system, and use purchased 12v DC landscape lighting. I plan to control each 'zone' with a ...
0
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3answers
78 views

Switch PWM signal to two destinations

Sadly i am not really experienced with electronics, i have recently obtained an Arduino and a motor driver and i am trying to hookup some lego motors. My motor driver outputs 2 signals, one for ...
2
votes
3answers
155 views

Transmitting PWM binary at 400kbps (or 800kbps)

I need to send a string of bits to a chained set of RGB LEDs, each of which have their own controller IC. The datasheet for that IC, the WS2811, is here. The protocol is quite simple: each bit, both ...
2
votes
2answers
123 views

PWM and DC motor speed [duplicate]

I'm hoping to try to control the rpm of a DC motor. AFAIK, I'd need to generate PWM for that. How does one find out which frequency is needed for a certain rpm? Is the frequency of the PWM signal ...
3
votes
2answers
81 views

Timing Issues with Optically Isolated Data Signal

I have been working on a system that requires data transmission between two devices powered by separate supplies. I have based my design on the MIDI-hardware Spec, as I'm comfortable working with that ...
0
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2answers
41 views

Will a PWM-Enabled MCU Work With Any Motor?

Why do so many MCUs specify what kind of motors they work with? For example: http://www.microchip.com/pagehandler/en-us/technology/motorcontrol/ Surely, the MCU has no concept of a motor and it ...
22
votes
4answers
1k views

Does (and when how) the lifetime of a LED depend on the PWM frequency

Let's assume two options for driving a standard LED at its rated current. PWM set to 50% duty cycle at 10 kHz PWM set to 50% duty cycle at 50 kHz Technically both LEDs would produce the ...
0
votes
1answer
45 views

PWM created from 16-bit timer and 32-bit timer

I have a question that does the PWM created from 16-bit timer differ from one created from 32-bit timer. Personally, I deem that they are the same, since by taking the fourier series of the PWM ...
3
votes
4answers
128 views

LED dimmer for high current applications

Hi Guys .. I am designing a few panels using LEDs for backlighting. Some of these panels have over 20 leds, using a 5v power source. So only one of these panels can draw around 500mA alone. I am ...
2
votes
2answers
108 views

Powering LEDs with a transistor

I'm a beginner. I'm designing a battery powered LED flashlight with a dimmer. The flashlight will have 3 LEDs and the dimmer will be controlled by a PWM signal generated by a 555. The circuit is ...
3
votes
3answers
641 views

LED: should I smooth the current with a capacitor

To control the brightness of a LED often pwm is directly used as input to the LED. Does this on/off turning by the pwm has any negative effect on the live expectation of the LED? Would it be better ...
0
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3answers
75 views

Help with low-pass filter and TTL logic interface

I am working with a motor control board which controls a DC motor (speed and direction). This board uses two SPDT relays for direction, and some sort of PWM for speed. Here's an abbreviated ...
2
votes
2answers
105 views

Detecting Specific PWM Signal Without Programming (Only Electronics Components)

I want to detect a specific PWM signal by electronic circuit components i.e. transistors, opamps, capacitors. update: I want to build simple ID system. I want to detect specific PWM signal for example ...
0
votes
1answer
81 views

TimerA: How to get PWM in upMode configuration?(TI MSP432 Launchpad)

I try to use UpMode timerA configuration on MSP to get PWM with arranged Duty Cyle. So here is my code below: ...
4
votes
4answers
779 views

Why do motors buzz when are applied PWM?

Why do motors (DC) make a buzz sound when a low duty cycle PWM is applied to them? Once I applied a 10% duty cycle PWM to a gear motor and it didn't move. just made a buzz sound. What does a low duty ...
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1answer
69 views

Can timer2 control the pin “oc0” in ATmega32a?

On a board the input of a PWM controlled device is tied to the pin oc0 of an ATmega32A and it's not changeable (it's a PCB). Timer0 is busy and can't produce PWM to ...