Tagged Questions

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

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1answer
86 views

Transistor amplifier circuit for triangular wave

I've made triangular wave oscilator as shown in Fig. 1 and it works perfectly at frequancy 10 kHz with peak voltage +3 Volt to -3 Volt. I intend to generate SPWM. But when I feed this circuit to ...
-5
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0answers
44 views

PWM from 1v to 5V convert to 12V

guys thanks for time and help... i need to convert the signal of pwm output the pwm signal cand delivery from 1v to 5v i need to read this signal and boost to 12V for on/off relay where i can find ...
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2answers
26 views

Inverted PWM with ATTiny10

On a 10MHz ATTiny10, the following code generates the same 40kHz 50% duty PWM on both pins 0 and 1: ...
1
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3answers
40 views

HEXFET PWM motor driver does not work

I'm trying to drive a motor for an academic project, using the circuit in the image. The STM32F4 Discovery board that I'm using in this phase of the project produces a 30Khz PWM at 3V, that is correct ...
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0answers
35 views

PWM and brushed DC motor - AC input? Limiting RPM?

I'm looking to replace the 20-year old poorly-performing speed control in a MIG welder. It allows the user to adjust the speed of a small brushed DC motor, which drives thin welding wire of of a ...
0
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3answers
76 views

Detect a missing PWM signal in the smallest possible board space

I have a motor control board that basically has zero space left, and the customer wants to add a fault flag to tell if their 2 kHz PWM input signal is lost. So basically, I need to detect a lack of ...
0
votes
1answer
28 views

Voltage wave form across a DC motor driven by a transistor with pwm

Above is the simple implementation for a DC motor control with pwm. I was expecting to see a square wave with a Vmax when Q1 is ON and zero when Q1 is OFF like the one here: standard pwm But ...
0
votes
1answer
36 views

How does this motor drive circuit work?

The Drive terminals are connected to a PWM signal generated by an arduino micro controller. The purpose of this circuit is to isolate the arduino from the motors to avoid too much current being drawn. ...
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0answers
39 views

STM32 - Multiple channel PWM input

I am using an STM32F405 based board , (OpenPilot revo ) to receive PWM signals from a joystick receiver . i have to xapture 5 PWM signals using only two timers , the timer 8 and the timer 12 . I've ...
2
votes
2answers
145 views

Convert positive square wave to positive-negative

I am looking for a way to convert a square wave coming from a microcontroller with voltage range from 0V to 5V, to a voltage range from -12V to +12V. The frequency of a square wave will vary from few ...
0
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3answers
62 views

How to up-convert PWM frequency without using a microcontroller?

I am trying to drive a motor H-bridge, but my control system can only support a 400 Hz PWM signal (black box, can't change it) which gives the motor an extremely loud 400 Hz whine as you would expect. ...
0
votes
1answer
61 views

Temperature stabilization with PWM , PID controller with delay system

I am doing a project to control the temperature with PWM. I use peltier, thermistor,mcu and h-bridge mosfet. I want to reach a temperature with an error less than 0.05 and stay at that temperature ...
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2answers
40 views

DC - DC Amplifier for Piezo Buzzer

I have a Raspberry Pi outputting a 3.3v DC square wave that I'd like to be able to amplify to just under 20v, the maximum the piezo can handle. Just to clarify, the piezo does not have an internal ...
0
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0answers
27 views

Pulse frequency for a pulse width modulation application

How can I determine the pulse frequency for a DC motor speed control or an LED brightness control. I have no data about the DC motor and led frequency dependence they both do not provide anything ...
0
votes
2answers
48 views

Basic h-bridge motor driver circuit for audio PWM waves with possible negative voltage

I need to control a DC motor with the PWM audio waves coming out of the audio jack of a device. The device will send a positive PWM to drive the motor forward and a negative PWM signal for driving it ...
1
vote
1answer
64 views

What is PWM Dead Band and when should I use it?

I'm having trouble understanding this concept, here is what the documentation in my microcontroller says about it: dead bands are defined as the number of PWM clock ticks from the rising or ...
1
vote
1answer
55 views

Mosfet life expectancy?

How to determine the life expectancy for the given mosfet? Mosfet : IRFP460 Mosfet Datasheet http://www.vishay.com/docs/91237/91237.pdf Actual Voltage,Current and other specification. Vds = 180VDc ...
0
votes
1answer
36 views

What is the name of the IC that runs a low-harmonic power supply?

I'm interested in building an AC/DC converter for low-harmonic applications. Single-phase AC input, followed by a rectifier and a PWM-controlled boost converter. I know there are ICs which are ...
1
vote
2answers
70 views

How to find duty ratio of a PWM using input capture?

I have a controller PIC18F and it supports input capture peripheral. I understand it can be used to find the frequency of the incoming signal. How can the duty ratio of PWM can be obtained from the ...
1
vote
1answer
46 views

Analog PWM generator from 0%

I have to prepare easy analog PWM regulator which can operate from 0% (0V). I know that one 555 can't do that... Do you know any circuit that can handle that?
1
vote
1answer
67 views

One PWM timer to two outputs?

first post here, so sorry for any bad styling. I'm working on a group project and using an Atmega328, without going into specifics, I need to drive two fans, two servos, and 1 CTC based function from ...
0
votes
1answer
48 views

Generate PWM signal based on 555 for Meanwell LDD driver

I am using a Meanwell Led Driver LDD-1000H. It has a single pin for PWM input for dimming. I have seen many sketches using the 555 to dim a LED but in these cases the LED was part of the circuit. How ...
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0answers
21 views

Controlling ESC with Arduino [migrated]

I want to control these motors: hexTronik DT750 Brushless Outrunner 750kv with this battery: Turnigy 2200mAh 3S 25C Lipo Pack and these ESCs: TURNIGY Plush 18amp Speed Controller. I am new to this ...
3
votes
1answer
114 views

Brushed DC motor control MOSFET selection

I want to control a brushed DC motor of the below specification: Motor: Permanent magnet DC brushed motor Voltage: 180V Current: 5 Amps RPM: 1500 The control method is PWM switching through a ...
0
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0answers
48 views

PWM to proportional bipolar control with push-pull amplifier. Need input and opinions

I'm putting together a circuit to control a (small wattage) TEC device in a bipolar manner. The idea is to have a micro controller put out a 3V3 PWM signal, level shift it between +- 3 V and filter it ...
1
vote
1answer
99 views

Adding more LEDs to a current regulating circuit

I am modifying a current regulating circuit that was designed to power three LED lights (see figure below). The circuit is designed to maintain current through the LEDs at 1A. The LEDs should be off ...
0
votes
1answer
69 views

Inductor calculation for DC to DC converter

How can I calculate the value and characteristics of inductor in a DC to DC converter?
1
vote
2answers
170 views

Microcontroller PWM to bipolar push-pull amplifier issues. (level shifting)

I'm trying to design a circuit that allows a micro controller (arduino) to control a voltage to a load. The load voltage needs to be bipolar in nature (+- 3 to 5 V) for use in controlling a TEC. My ...
1
vote
3answers
139 views

Sin signal from PWM

I wrote a program in order to use Pulse Width Modulation to simulate a sinusoidal signal. Added a low pass filter to get rid of the noise and the traces of it being a discrete signal. Added a half ...
0
votes
0answers
67 views

Generating and measuring PWM

Description of the main part of my project: A microcontroller should read 4x PWM channels, that come from a RX1. The frequency of the PWM signal is fixed (about 50Hz), the high time of the pulse is ...
0
votes
2answers
80 views

PWM control of air core motor

I am driving an air core motor using PWM control from a microprocessor. The position of the air core is dictated by the combined magnetic field created by applying 2 currents to 2 coils (sine coil ...
0
votes
1answer
141 views

How to replace bulb with LED in a PWM circuit (car)?

I want to replace a light bulb in a Peugeot 308 SW with a LED. The bulb works (lights) normally, but the LED blinks. I thought they are controlling the bulb in alternative current but my digital ...
0
votes
6answers
101 views

Converting PWM to bidirectional square wave?

Is it possible to make bi-directional ( symmetrical) square waveform from PWM signal? Im talking about 40 kHz frequency and 0.5v /-0.5v peak to peak signal.
1
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2answers
254 views

How to make a 12V DC variable voltage supply with more than 30A output?

I have a SMPS capable of outputting 33A at 12V and I would like to make it have a variable output with full current potential, or close to it. Now, Is it possible to do it with a PWM-controlled ...
0
votes
3answers
82 views

PWM controlled variable resistance

I found this circuit design for constructing a variable resistor. Its seems that the resistance can be controlled by the duty cycle of PWM on MOSFET. Would you explain what is the purpose of having ...
1
vote
0answers
70 views

PWM only works after touched with oscillicope probe

I am using two PWM outputs from a Netduino 2 to control two servos. One of the PWM pins works perfectly fine but the other doesn't work until I have touched it with an oscope probe. The probe doesn't ...
0
votes
2answers
124 views

Build variable resistor controlled by Arduino

I would like to build a variable resistor that can be controlled by Arduino. My plan is to vary resistance between the two values, i.e., 1 ohm to 10ohm, to continuously change the load for a small ...
0
votes
2answers
91 views

Opening MOSFET's gate with low voltage PWM

I have PWM of very low frequency and very low duty cycle. And max voltage comes out are 3.3. But thats not enough to open the MOSFET's gate(IRFP250N). Now I want to amplify the voltage. I do not have ...
0
votes
0answers
27 views

Emulating, tricking or faking a liquid cooling sensor

I have a specialty server board with an attached liquid cooling system, the liquid cooler has 3 pins attached to the board, pin 1 gnd, pin 2 12v+, pin3 sense. I'm assuiming this works like a cpu fan. ...
0
votes
0answers
54 views

MSP430 PWM Dead-Time

According to the internet, the MSP430 has no hardware implemented to maintain proper PWM dead-time as the PWM duty cycle is modified. Apparently (and also according to the internet) this feature can ...
1
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2answers
63 views

Generate PWM signal using GPIO

I want to generate a software PWM signal for 5 millisecond. using GPIO with 50 percent duty cycle and 100 KHz. ...
1
vote
1answer
71 views

How to calculate PWM duty cycles for Solenoid current control

How to calculate the PWM duty cycle for Solenoid current control I am trying to design a current control driver for Solenoid. I know the peak and the holding current range for solenoid. How would I ...
0
votes
2answers
98 views

Is it possible to use a ULN2003A Darlinghton array instead of multiple TIP120 transistors?

Looking at the datasheets, I'm not sure their specifics match; TIP127 and ULN2003A My intention is to do something like this, but with the ULN2003A, that I have already: The reason why is that I ...
2
votes
1answer
84 views

Eliminate PWM noise in PWM-driven bidirectional motor

I need to drive a DC motor with PWM, through a H-bridge. The controller can't generate PWM at ultrasonic frequencies with resolution I desire, and the low-end of the spectrum (~100Hz) may be too slow ...
1
vote
2answers
163 views

MOSFET gets hot when PWMing car high beams as DRL lights

The idea of this project is to have my car's high beams work as daytime running lights (DLR), with reduced light output. The DRL would turn on with the ignition on, and turn off, either when the ...
1
vote
1answer
78 views

driving LEDs via a PI a attiny and TLC5940 (validation) and possible powering issues

at the moment I am planning my first real (big) electronics project. I want to build a LED lamp, that can be controlled by a RaspberryPi (for e.g. programming a binary clock or changing the brightness ...
4
votes
3answers
565 views

What are some problems with running a heating element in PWM mode?

I want to be able to control a heating element's (which runs on 230V mains) power level, and I'm thinking of running it using a solid state relay and PWM. However, I'm unsure of the implications of ...
1
vote
2answers
159 views

RGB LED strip, powered by an ATX PSU and controlled by PWM, makes my speakers buzz with Arduino connected by USB

I've not much idea about electronics, but I managed to do some little projects in the past. Now I'd like to place some RGB LEDs in my desktop PC windowed case. For that, I bought a 5050 SMD strip with ...
2
votes
1answer
34 views

PWM or switch port programmatically for Servo

Is there a huge difference between using a PWM and switching a port through a program (like using switch) for operating Servos? For smooth movement is PWM necessary or switching using a program will ...
3
votes
4answers
156 views

Why do most PWM LED displays and backlights operate at a relatively low frequency?

All around me are a bunch of electronics: digital clocks, my laptop, a refrigerator, a dimmable flashlight, and more. What they all have is perceptible flickering of their displays due to PWM, ...