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Questions tagged [pwm]

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

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23 views

TLC5940 SOUT/SIN signal broken after 4th daisy-chained IC

I have a PCB with 5 TLC5940's daisy-chained. The first 4 work fine, but the fifth doesn't work. The LEDs connected to that one just go on at full brightness and that's it. When I measure the SOUT to ...
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1k views

I found an audio circuit and I built it just fine, but I find it a bit too quiet. How do I amplify the output so that it is a bit louder?

I want to try something audio related and found the following circuit from technoblogy I built it and loaded a sound clip. Everything works fine, but I found it a bit too quiet and I want to amplify ...
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50 views

PWM Not Driving IRL520N MOSFET

I am trying to switch a IRL520N logic-level MOSFET using a 0-5V PWM signal from my microcontroller (PyCom FiPy). I tested just the MOSFET with a 10 Ohm series gate resistor and my load is a 9-15V ...
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29 views

LTSpice PWM Signal Showing Capacitor isn't Fully Discharged

I'd like to create a pwm signal input to mimic a real life situation of a pwm input that shows the capacitors aren't fully discharged. Please see the image below. I am currently able to create the pwm ...
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2answers
82 views

Why does the MIT Racecar not use the build in ESC?

MIT has build an autonomous RC race car. They put everything on GitHub. I have a similar project and therefor build one of those for my self (Almost the same but without TX1 and Sensors). I am ...
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29 views

Is the same send a pulse with 5V than reduce voltage with driver? [on hold]

I've a conceptual question: if I send a PWM to a MOSFET that drives a Motor with 5V, is the same than using a driver to send from 5 to 0V? For example and be clearer, is the same send a %50 duty ...
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1answer
55 views

Class D Amp headphones grounding circuit

I am having a problem with some of the class d amps I've played with (PAM8302A), and it seems like this article here describes my problem: https://www.edn.com/design/analog/4313726/Add-headphones-to-...
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72 views

Light sensors sensitive enough to detect for PWM from CF and LEDs?

I have an extreme sensitivity to PWM light sources such as computer screens and light bulbs. This can make it very challenging to make a purchase as I end up having to do lots of guesswork with ...
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Arduino PWM & MOSFET successfully control LED but not electromagnet? [duplicate]

I've got an Arduino circuit set-up so I can control the strength of an electromagnet using a potentiometer. My potentiometer is hooked to A0, and I'm mapping its value to PWM pin 3 which then goes to ...
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1answer
57 views

Unexpectedly high voltage drop in the transistor

I'm driving an LED with a microcontroller through a transistor with a PWM signal. When the gate is grounded, no current flows, as expected. As soon as I start to drive the transistor (1% duty cycle), ...
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36 views

Convert 2 wire pwm signal to servo control pwm

Bit of a weird one - got a controller that has a variable 12v PWM output (~100Hz), I can't change this output as the signal controls other devices, I haven't got an oscilloscope but I belive it's ...
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28 views

transformer to work in sinePWM waveform

How to design a transformer working with PWM waveform with the following data: fundamental frequency:50Hz, PWM switching frequency 10kHz. The transformer secondary should also be a PWM output, just ...
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0answers
36 views

Three level PWM modulator circuit feedback simulation

I'm trying to design a three level PWM circuit with feedback and i'm struggling to understand the feedback aspect. The design is based on this design by Texas instruments and modified to suit three ...
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1answer
59 views

Modifying a PWM signal

I have PWM signal from a computer motherboard to control 2 fans, one of them is rated for 3000 RPM, and the other one is rated for 2000 RPM. I'm trying to run all of them at the same speed(for ...
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2answers
45 views

555 Timer PWM generator

I have the following circuit for a 555 Timer PWM generator: With 1: GND, 2: TRIGGER, 3: OUTPUT, 4: RESET, 5: CONT, 6: THRESHOLD, 7: DISCHARGE, 8: VCC I dont quite understand the use of R1. Is it ...
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79 views

PWM to synth control voltage improvements

Just built this little circuit to control my Moog Werkstatt. The plan is to make a MIDI-to-CV converter and add more CV outputs and of course a GATE output later. But before going further, I thought I'...
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47 views

PWM output with Teensy 32. Atmega32u4 failing when printing values to terminal

I am implementing PID control and have developed code that reads analog potentiometer inputs, converts it to discrete counts, and outputs a PWM response to a DC motor based on the angular displacement ...
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1answer
26 views

PWM phase voltage and current measurement for power consumption calculation for a BLDC MOTOR

I have been trying to log both voltage and current from the battery of an electric two wheeler for finding out efficiency at inverter, battery level.
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34 views

Controlling a PWM'ed DC fan from 24v instead of 12V source

I have a tiny 12V which consumes ~0.07A and i was wondering if i can PWM the 12V fan with a 24V source at a 50% duty cycle through a ardunio and a mosfet. Would that work or fry the fan as the voltage ...
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6answers
103 views

Optocoupler Characteristics

In my application I need to isolate a PWM signal @ 1 kHz, which is generated from a Beaglebone Black microcontroller. In my signal, I want to have one hundred different steps in duty cycle (from 1% to ...
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2answers
80 views

How can implement a low pass filter with this PWM signal? (Deadstop Fan won't start error)

I want to low pass the signal to the fans in this circuit. PWM frequency is 35khz and I calculated that I would need C = 10 µF and R = 10 Ω But no matter how I place my capacitor and resistor, ...
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1answer
42 views

Can we apply a longer pulse to latching solenoid than its rating?

I've a 6-12V dc latching solenoid, which needs 60ms of pulse to set it to on/off. I'll be using a microcontroller to generate the pulse. I've following questions. What if the generated pulse is ...
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13 views

Freescale HCS08 PWM

I am using freescale HCS08sg8 Micro controller. here am set a fixed period and different duty cycle. My problem is first pulse width is higher then the other pulse width. am using code worrier V6.3 ...
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20 views

Uncertainty in current values of Power HD digital servo motor

In a project, we want to lift the load of 5 kg on the ground to half a meter. For this purpose, we use a 360-degree rotating PowerHD digital servo motor with a stall torque of 20 kg / cm. Motor ...
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61 views

Converting 0-5V PWM to 0-10V PWM using Arduino and Mosfet not working

I am trying to convert 0-5V PWM coming from an Arduino to 0-10V PWM to run a motor which has PWM line that operate for 0-10V. But as soon as I connect the PWM line to mosfet it either shows only ...
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50 views

A simple circuit for pwm pass through only enable pin is high (or low)

I will have a PWM signal (it comes from other board) along with a single digital pin for enable or disable purpose. However my target board only has PWM input to control its output, using the PWM ...
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1answer
35 views

DC bus correction for inverter VFD via PWM modulation

This is a question concerning an inverter circuit without PFC. Single phase AC is rectified and pooled on DC bus capacitors. From there the DC voltage is modulated at 5kHz on 6 IGBTs, emulating ...
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1answer
31 views

Synchronous vs asynchronous PWM modulation

According to Mohan/Power Electronics, asynchronous PWM modulation results in subharmonics that are very undesirable in most applications. We can use this type of modulation only if we choose a large ...
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1answer
16 views

How Simulink determines the amplitute of the carrier in PWM generator

In Matlab/Simulink, we can use the PWM generator block in order to create pulses. So, according to this method, the carrier is compared to the reference signal in order to create the pulses. In ...
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2answers
63 views

DC motor characteristics

I have a PM DC motor. I am controlling the motor speed using PWM. I wanted to know what is the relation between the torque vs dutycycle and speed vs dutycycle for the motor( given the fact that the ...
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4answers
102 views

Could someone explain dither signal?

I know that regarding proportional valves the dither signal is a signal superimposed on PWM command that actually moves the valve. It improves the response of the valve because the coefficient of ...
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1answer
51 views

Drive a resistive heater from a low power IC

I'd like to drive a resistive heater using an IC operating at 3.3 V. The heater may need to dissipate up to 18 W, and will be powered by a 28.8 V battery. The IC is able to generate PWM signals, but ...
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1answer
43 views

Channel 4 in STM32 Advance Timers TIM1 and TIM8 [closed]

There are advance control timers in STM32 family as in STM32F407 and these are specially suited for 3-phase (or 1-phase also) motor control applications using full H-bridge. These timers provide ...
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1answer
53 views

voltage traces across pwm driven dc-motor: is that ok?

I'm driving a dc-motor with a BJT turned on and off with a 555 generated PWM signal. Here's the circuit (V1, Rl and L1 simulate the motor): There actual circuit - same parts - is on a breadboard and ...
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1answer
64 views

High PWM frequency weird shape

Using a STM32F407 if I generate a 200 Hz signal it looks like this: If I want a higher frequency, for instance 10 kHz I get this: I am using a PicoScope 2205A, resolution 8 bits at 200Ms/s, ...
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31 views

BLDC hoverboard motor with no specifications

I have this kind of motor but I can not find any electrical specifications about it. All I know is that is a 36V,250W BLDC motor. How can I determine the number of poles, the coil resistance/...
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2answers
55 views

Analog signal exchange between microcontroller and PLC

Overview I need to create an analog voltage of 0V-24V for the PLC ( s7-1200) with a microcontroller with operating voltage 5V. Approach I've been doing this research since yesterday. I'll share ...
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0answers
35 views

High side N-channel Mosfet Switching output port short circuit protection

I have designed High side plus low side isolated combined N-channel switching using mosfets for high power switching through Mosfet. The power handling of the design is 24v/70Amp. The design is ...
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1answer
619 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
41 views

LED-strip PWM works with Raspberry Pi, doesn't work with Attiny45

I'm trying to control an RGBW analog LED-strip by PWM modulation. When using an Attiny45 the LED-strip just blinks at a low frequency (approx. 2-3 hz). However, using a Raspberry Pi 3 to control PWM ...
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1answer
170 views

12V PWM controller for 12V fan that gets faster with the COLD

I need a controller for a 12 V - 1A fan, blowing on the cold side of a Peltier element to keep it at constant temperature. I have the hot side under control. I have seen multiple cheap PWM ready-to-...
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2answers
56 views

Analogue signal generation: Which is better Standalone or PWM DAC?

Most controller/processor come with PWM output and integrated standalone DAC module.... My need is to generate 50/60Hz analog signal for testing purpose! Which would be the good choice PWM DAC or ...
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1answer
103 views

PWM with ADC - ATMega16

I want to write code where I move the wiper of the potentiometer clockwise so it applies PWM on a pin, and when I move it counter-clockwise it applies PWM on another pin. I could do it with Arduino, ...
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1answer
29 views

Error Amplifier Gain

I was studying the "SG3525" IC and its functions, and I encountered this issue: In the "Error Amplifier" section of the Datasheet, there is a parameter that named "DC trans-conductance" which it is "...
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5answers
136 views

15% drop in motor RPM when using PWM controller

I'm new to the forum and a total noob to electrical engineering. I have a 120W, 24V DC gear motor. Runs at ~200 RPM no load connected straight to a 24V power supply. However, when I connect it to ...
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0answers
44 views

STM32 HAL PWM output with DMA misbehavior

I use the Blue pill STM32F103C8T6 to generate variable duty cycle PWM with DMA and using HAL library. And stuck with undesired results. First, I generated code with STM32CubeMX v5.0.1, HAL v1.7.0, ...
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1answer
48 views

Creating Neutral node on Three phase Inverter

I want to create a neutral node at the output of a 3-phase Inverter for ACIM. Is it possible to do that by adding 3 resistors at the Inverter outputs and join them together to get the neutral node? ...
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1answer
136 views

Processor speed for generating PWM at 1 MHz

I want to generate square pulses at around 1 MHz to drive an H-bridge inverter. Now, I want to choose a suitable microcontroller, microprocessor, or a DSP board. I need to generate a few pulses (...