Questions tagged [pwm]

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

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30 views

+-10v input motor driver

I have a servo controller that outputs a +-10v velocity command for a motor. how can i take this signal and turn it into a pair of PWM outputs to drive an H-bridge? a value of 0 to 10v will control ...
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3answers
67 views

How does a microwave oven modulate its output power?

My microwave has multiple power settings, ranging from 500 watts to 1500 watts. My question is how is the power reduced/modulated? I can think of a few options (but I don't know which one is correct/...
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which IC produces PWM that can be filter into sine wave?

For a DC to AC transformerless power supply, I am trying to find a specific type of IC that produces PWM that can be filtered into sine wave. What I can find in most website is MCU that has to be ...
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62 views

What’s the difference between led current draw with and without PWM?

I have a LED that’s rated for 3W (aprox 3V and 1A max current) Do I get the same result in terms of current draw and led’s durability if I supply the led with a 1A Led Driver (at full current supply, ...
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1answer
37 views

High Power LED Circuit Design & Constant Current Source Question/Feedback

I'm trying to design a dimmable LED circuit board. It's controlled by Arduino with its PWM signals. I'm new to electronics so I have some question regarding my design and knowledge on it. I've ...
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1answer
75 views

FM demodulation (not!) using PLL?

I have to demodulate a square wave FM+PWM modulated signal, so for the FM demod I'm using a PLL with a positive edge sensitive comparator to lock on frequency only (CD4046BE). Carrier frequency is ...
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1answer
53 views

Linear Actuator using Relays, MOSFET, and PWM

I have a 29V Linear Actuator that I want to control - both direction and speed. For the direction I used this 4-channel relay module, but I only used 2 relays on it. I was able to successfully ...
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1answer
57 views

spwm look up table {For bldc control}

I am trying to implement sinusoidal control in BLDC motor. After doing some research about sine wave controller. spwm and svpwm are the better controlling methods for sine wave controller. So I first ...
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isolated 5v PWM to 0-10V

I'm trying to convert a 5V PWM signal to 0-10V through an optocoupler to drive a VFD. The output "0-10V" should be 0V when PWM duty cycle is 0%, and 10V when 100% (linearly !). Here is what I've come ...
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62 views

How to generate a periodic signal?

I want to generate a signal like this one: My first idea was to generate a PWM with different duty cycle and different frequency but I don't really know how to do it with STM32F1. Is that a good way, ...
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1answer
35 views

Comparator problems with output

I am kinda new to electronics design and I am having some trouble with the Analog Devices LT319AN chip. I am trying to do simple 250KHz PWM which worked on a lesser LM393 chip in this exact setup. I ...
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2answers
56 views

Controlling a 0-20mA transmitter from an isolated PWM signal

I'm trying to generate a 0-20mA signal for controlling an industrial actuator (the position of a 3-way valve) from a Teensy 3.2 system. Preferably, the mA-output should be galvanically isolated from ...
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4answers
203 views

Measuring voltage drop across a diode in a switched circuit

I have the below circuit where the input voltage is 8V and a PWM pulse is given to the base of the Q101 transistor. From what I have measured, The voltage at the anode of the diodes D102 and D103 ...
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2answers
57 views

LED PWM with FOD8342 Optocoupler

I'm trying to PWM some high power LEDs from a isolated control line using a FOD8342. It worked on the bench when prototyping, but now it's part of the final design it seems to work for a minute then ...
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1answer
40 views

ESC signal standard and PWM frequency

I got the following code from the video. However, I encountered an issue that, the motor tended to stop working at maximum value. ...
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2answers
70 views

Getting 12Amps of 0-12VDC from relatively low frequency PWM

I am trying to drive 4 parallel TEC elements. (TEC1-12706) I intend to run them together up to 12A (or 3A each.) I am using an ATMega328p (in the form of an Arduino Uno Board) to control the system, ...
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43 views

Fast switching ULN2003's GND Pins

IO Expander MCP23017 is used to drive ULN2003 which drives 24v relays. 60% PWM power to relays cause them to heat less. As MCP23017 doesn't have PWM output, thought of switching the ULN2003's GND (...
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2answers
78 views

How to calculate speed of DC Motor?

I have a DC motor rated 24VDC@200mA driving at 40% DC and 20% DC(PWM) should run at what speed? Is there any formula to calculate the motor speed based on duty cycle
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1answer
49 views

AC dimming with STM32 timers

I'm using an STM32 for AC dimming, for which I use a GPIO output (or timer channel out) to drive a triac, whenever I get a zero crossing detection (rising edge). Is there a way to solve this only ...
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2answers
38 views

How to model the motor for this PWM motor driver circuit and is this simulation reliable?

I want to control the speed of this brushed DC motor with PWM control by using a uC board like an Arduino board. So the PWM output is 5V and it can source only upto 20mA so I need to use a transistor ...
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1answer
45 views

Need help on a DC motor-PWM-SMPS setup (Does a PWM help overcome a DC motor's initial startup current surge?)

I am trying to build a DIY one-way peristaltic pump with a 12V 100W DC motor (possible candidate : https://www.ebay.com/itm/DC-12V-100W-13000-15000rpm-775-motor-High-speed-Large-torque-DC-motor/...
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2answers
70 views

How to amplify 3.3 volts PWM to 5 volts PWM

im working on a project to drive a motor using a motor driver that accepts 5 volts PWM (for 100% duty cycle) but im using raspberry pi 3 that has a PWM of 3.3 volts (for 100% duty cycle) as a result, ...
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0answers
27 views

Pulse width modulation for three phase voltage source inverter

I have found a block diagram which discribes implementation of a modulator for the three phase voltage source inverter. I am not sure whether I fully understand this implementation of the modulator. I ...
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1answer
46 views

ESP32 Sample a 1kHz square wave (10%-90% duty cycle) with analogRead()

I need to sample the peak voltage of a 1kHz square wave. The duty cycle varies between 10% and 90%. I am using an ESP32 and hoped to use analogRead() to sample the data. My first idea was to attach ...
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1answer
40 views

Is it nessesary to use PWM pin on LMD18200

I'm creating the circuit which has to apply direct and inverse voltage to the load and I want to use LMD18200. According to it's truth table, if I connect PWM to logic ...
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1answer
24 views

A question about controlling pm DC motor with long signal wires

I have a PWM driver board for a 12V pm DC motor(like toy motors) to control its speed. To create a shake effect the motor will be mounted 50 meters far away from the PWM driver board, for such long ...
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1answer
34 views

stm32f1xx how to use DMA to write to TIMx CCR

I am trying to control WS2812b digital LEDs with stm32f103. I have a buffer of color values for the LED strip and to transfer them I need to write the next value to the timer's CCR every time the ...
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1answer
57 views

Can I use a PWM controller to control the speed of a motor? [closed]

First off, I’m starting electronics as a hobby so excuse my lack of knowledge about electronics in general. As a staring project, I was going to try and make a magnetic stirrer to use in a chemistry ...
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2answers
41 views

LED Driver with relatively high capacitance on PWM input causes PWM signal to be laggy

I am using three Meanwell LDD-600L LED drivers (datasheet) to control brightness/color of a 50 Watts (total) RGB LED. This driver has a PWM input which I draw low with a PC817 opto isolator. ...
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1answer
44 views

Using LED driver as PWM digital outputs

I'm building a robotics project where I need to control a lot of DC motors. I picked the DRV8870DDAR H-bridge motor driver chip which needs 2 PWM input signals to control the speed and direction. ...
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1answer
95 views

stm32 which timer and DMA channel should I use?

I am trying to control two lines of digital LEDs (WS2812b) with my STM32F103 using Timers with DMA and PWM. LED strips data lines are connected to PB5 and ...
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54 views

Noise level detector circuit design (AC to DC to PWM)

So I'm building a sound level detector. Design requirements are: Only basic circuit elements No IC's, except for op-amps Sound level will be displayed with a blinking LED Blinking LED will be ...
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2answers
76 views

Convert 5V PWM Arduino Signal into 12V signal that can deliver 100mA

I am an electronics newbie and I want to convert the 5V PWM signal from an Arduino into a 12V PWM signal which delivers 100mA (rms). How would such a circuit look like? I tried with OpAmps and got the ...
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2answers
75 views

How to invert PWM signal on STM32

I am trying to control a WS2812 LED with STM32F103. The LED is a digital RGB LED also known as Neopixel. They are controlled by sending 24 bits of color data per LED to the first LED's data pin. The ...
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2answers
69 views

65V Square wave Switching Circuit

I am trying to generate a 65V square wave very similar to the post found here: Mosfet PWM signal not square My load is in a slightly different configuration (i've tried them both ways), but the ...
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2answers
65 views

Voltage output across purely capacitive voltage divider when PWM/Square wave signal is applied?

Having some trouble with understanding the voltage output in time domain across a capacitive voltage divider when applying a square wave from 0 to 5V? It can be assumed that the capacitors have some ...
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1answer
47 views

Measuring voltage from automotive PWM dimmer circuit

I am building a gauge to replace another in my instrument cluster. I am adding some LEDs and an OLED screen and I would like them to have adjustable dim with the old incandescent backlight bulbs. I ...
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3answers
92 views

Convert 1kHz PWM signal to 0-10V DC with minimal ripple [closed]

For my application, I want to control the position of a valve which takes 0-10V input voltage. For the determination of the position I need to use a digitial 5V 1kHz PWM signal from an Arduino Nano. ...
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0answers
54 views

PWM with 555 timer IC

I am trying to build a PWM signal with 555 timer. I am following this website to build my circuit. simulate this circuit – Schematic created using CircuitLab I have placed my components in my ...
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1answer
53 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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1answer
30 views

How to Cascade Filters and Audio Volume Control

I am trying to output PWM from an MCU, filter it with a LPF to form an analog signal, cascade an audio volume control that allows for smooth control between silence and a somewhat amplified signal, ...
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Carrier shape in PWM

I'm creating a PWM model in Simulink by using repetitive signal (carrier) and some input (reference signal). I was wondering what are the things that I should consider when I choose sawtooth or ...
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0answers
26 views

Driving Headphones with ATmega324A

Background: I am considering the Texas Instruments TPA6138A2 as a combined headphone amplifier/low-pass filter solution to convert two 0-5V PWM signals from an ATmega324A (which can source/sink up to ...
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55 views

Si8234 PWM with “disable” pin

in the datasheet of the Si823x family of gate drivers, the Si8234 is mentioned as being a high-side/low-side driver with PWM input, but actually this "PWM" input pin is only there for switching ...
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1answer
32 views

How to synchronize readings with the HIGH and LOW states of a PWM output?

I would like to oscillate GPIO infrared LEDs at a high frequency and compare the infrared sensor readings when the LEDs are off and when they are on. To do this I would need to synchronize the ...
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3answers
69 views

RGB Controller, switching frequency interferes with IR receiver

I am trying to build a color fading RGB controller with an ATmega328, three MOSFETs and an TSOP4838 IR receiver. The RGB LED is 50 Watts and is driven by a 45 Volts off the shelf switching power ...
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2answers
58 views

Magnetic force as a function of PWM frequency

Consider an experiement with a DC source feeding an coil with a constant DC current I. The coil with an iron core attracts a magnetic plate with mass m with force F. The force F is higher than Fm and ...
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1answer
80 views

Perf board parasitic capacitance fries microcontroller?

Recently one of my mirocontrollers fried in a project on a perf board. Eight of the outputs are PWM, and aside from the power lines, there are no other outputs from the MCU. The PWM frequency is 40 ...
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0answers
21 views

Capacitor(s) for PWM half-bridge output filter?

The output pulse train of a 250kHz half-bridge DC-DC converter contains harmonics well into MHz frequencies. The output filter requires capacitors in the 0.5uF to 1uF range. Datasheets show that the ...
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0answers
19 views

Op amp Type 2 Compensator with Uc3845

I came across this type of compensator to connect to UC3845 with 2 diodes (D3-D4). Why those diodes connect there? Is it necessary to put them? I have attached shematic.