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

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62 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 ...
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0answers
58 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 ...
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2answers
102 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 ...
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2answers
78 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 ...
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0answers
21 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. ...
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0answers
36 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 ...
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2answers
40 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. ...
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1answer
26 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 ...
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2answers
63 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 ...
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1answer
52 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 ...
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2answers
141 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 ...
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1answer
59 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 ...
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3answers
520 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 ...
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2answers
97 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
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1answer
32 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 ...
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4answers
120 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, ...
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0answers
46 views

Varying the Frequency of PWM Inverter Modulation Function

I'm modelling a PWM inverter with a triangular carrier signal, and a sinusoidal modulation function. In order to get certain frequency of sine wave out of the inverter, I need to vary the frequency of ...
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1answer
39 views

Board or product to drive 15 PWM/analog outputs from USB/serial connection

Ok, Let me explain: I would like to drive 15 analogs (0-12V) signal from my computer (based on user interactions/other not-so-cool stuff). This hardware has to be controlled over USB or Serial port ...
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0answers
89 views

BLDC motor control PCB

I am trying to make a PCB to control a Sensorless Brushless motor. I just wanted to know if it looks right. The IC I am using is a TB6588FG it has a 2.5A peak output current. I want to use it with ...
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1answer
70 views

Controlling current in a PWM circuit

I have a PSOC Cypress board which generates a 5V PWM signal to drive a laser diode. The idea is to design a programmable pulse which I could control the on-time period and current in the pulse. The ...
0
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1answer
37 views

Help for PWM circuit for 12 volts DC up to 1.3 A

Is there a way to do a fairly simple PWM circuit that will handle 12 volts DC up to 1.3 Amps? The 555 timers appear to fall in the 600 mA to 900 mA max power dissipation range. Attached is the basic ...
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3answers
80 views

EMI due diligence

I had an idea to use the World Semi WS 2801IC used for addressable led strips with a power mosfet driver so that each address can be tied to a high current (~1-1.5A) load. The chip indicates the PWM ...
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3answers
172 views

DIY current-limited 40A+ power supply to emulate LiPo batteries

I want to do some experiments developing brushless DC motor control hardware, and maybe wiring my own motors for my own edification. LiPo batteries aren't convenient enough, and I want ...
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2answers
282 views

Why is there so much overshoot in my LED circuit and how do I prevent it?

I'm trying to PWM a 5 meter RGB LED strip with a microcontroller. With this setup: simulate this circuit – Schematic created using CircuitLab I have built it on a breadboard and probed ...
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2answers
74 views

PWM control of Peltier with Arduino+Thermistor

I currently have this setup and would like to add automatic control over the PWM based on a thermistor reading. Any insights?
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1answer
58 views

Space Vector Modulation

Im looking to learn more about this topic so that I can implement it in an amplifier design. I've read around and understand most of the math behind it, but I'm still a little fuzzy on how to ...
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1answer
77 views

Shifting the phase of an Arduino PWM

This is a fairly simple question. Is it possible to use additional circuitry, connected to an Arduino PWM pin, to shift it's phase? As far as I can tell, the Arduino PWM pins can be configured for ...
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1answer
39 views

How to modulate Transceiver module for use with ATmega164PA

I am using a transceiver TFDU4101-TR3 to communicate with another device which has exactly the same transceiver. I bought this thinking I can communicate with the transceiver using my microcontroller ...
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1answer
100 views

How to use Turnigy MultiStar ESC with generic microcontroller? [duplicate]

I just got the Turnigy Multistar 20 Amp Multi-rotor Brushless ESC 2-4S. I have a motor and a battery hooked up to the ESC. On the three pin connector, I attached the brown ground wire to a ground ...
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1answer
93 views

n-channel MOSFET source load alternative

I'm trying to drive some RBG leds using MOSFETS. Let's say I have 2 individually RBG LEDS, each controlled by 12V, with each R, B and G with its own output to GND. What I want to control, is to be ...
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1answer
68 views

How to choose what a power supply to drive 2 x 10watt RGB LEDS?

I'm trying to figure out how to determine what power supply I should be using for different types of LEDs for this and future projects. I have 2 x RGB LEDS: Forward Current: 350mA Forward Voltage: ...
0
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2answers
111 views

Help to design an amplifier

I need help designing an amplifier that is capable of providing 1 W to an 8 Ohm speaker. I have 3.3 V, 5 V or 18 V supply available to power it. I also have only one power supply available that has ...
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0answers
40 views

Calculating power draw for LEDs and driver (TLC5941)

I am designing a backlit keyboard with 61 white LEDs. These will be individually driven by a TI current limited PWM driver (TLC5941). LEDs: 61 x Osram LCW JNSH.PC (Datasheet) Drivers: 4 x Texas ...
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2answers
66 views

Amplifier design

I am having trouble calculating values for this audio amplifier. Input comes from AVR PWM operating at 44.1 kHz with high being at 3.3V. The speaker is 8 Ohm and speced for 1 Watt. First two ...
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2answers
107 views

Variable Voltage Using PWM and Low Pass Filter

I am trying to control a steady DC output voltage using a Micro controller with a PWM duty cycle. With the current schematic, the Voltage on Vout is pulsing along ...
2
votes
1answer
123 views

Controlling speed of motor through L293D using TLC5940NT

I am trying to control a DC motor through an L293D. Ultimately I am controlling it with an Arduino, but I am trying to use a TLC5940NT chip as an intermediary to increase the number of outputs that I ...
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1answer
36 views

PWM input voltage regulation

I have a 12V DC motor that I plan to run in one direction with PWM input at 21A. However, in the other direction I want to drop the voltage to limit the speed. Ideally. the regulator would sit between ...
0
votes
1answer
112 views

Capturing PWM Signal on an Oscilliscope

I have a stepper motor that is controlled by PWM. I am trying to analyze the signal coming out of the controller on an oscilloscope. Ideally, I would like to capture, maybe 2 seconds of wave form so ...
0
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3answers
86 views

Capacitor on line with high frequency digital signal?

Capacitors act as a short for high frequency signals. If I place a capacitor on a digital 5V PWM line or perhaps a motor encoder line does the cap still act as a short to ground for the square wave ...
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votes
2answers
169 views

130V DC Motor Control

I am interested in building a control circuit for a motor. More specifically this motor. The model I want to control is the 130V model, 0.48A, which should make it at ~62W for the motor, and 1/17 ...
0
votes
1answer
66 views

PWM Dimming results in input ripple due to excessive inrush current

I use a constant current SEPIC boost regulator ([TI LM3410X) to run a 8.5V 400mA OLED panel from a single Cell Lithium polymer battery. I have noticed that the input voltage ripple is too much (~1V ...
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3answers
244 views

Can PWM be used for PID controlling…

I am was wondering if an IC like the PCA9685(Datasheet) that generates PWM signals can be used in a PID controller for controlling a heated bed on a 3D printer. My understanding of PWM is that it ...
0
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1answer
93 views

How does a true sinewave inverter work?

I am an Electrical Engineering student, and when we were taught about inverters (at a power electronics course) we studied inverters using Sinusoidal Pulse Width Modulation. My question is do the ...
-1
votes
2answers
58 views

Complex LED drivers/circuits [closed]

Throughout my travels I've seen these very complex circuits that incorporate ICs for "i.e. dimming applications" that are included in designs with buck boost converters, etc. What makes LED driving ...
1
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1answer
81 views

How do I replace an existing servo with a geared DC motor?

I am a complete beginner, just getting into the world of electronics, in particular robotics. I have found a really nice open source set up that I want to build on and change for my own ends. The ...
2
votes
1answer
94 views

How to build LED dimmer for room illumination - PWM, low pass filter?

I want to illuminate a room. This will be done by two LED strips 60led/m, each 5m long, located along the tops of opposite walls. In order to get full light power, they together consume 4A@12V. ...
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2answers
99 views

What is the reason my ULN2003A overheats?

I'm driving some 12v fan motors from a microcontroller using ULN2003A Darlington array. Both total wattage and per-channel wattage are way below ULN2003a limits. Still, I found that when PWM duty ...
0
votes
0answers
76 views

Voltage Sag with PIC24 PWM Open-Drain Configuration

I'm experiencing some major voltage sag with an open-drain PWM output into an RC servo. I'm pulling up to +5V with an external pull-up resistor. I've tried using everything from a 1k-100kOhm resistor, ...
0
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1answer
46 views

555 servo controller “modulation input”?

Exactly as the question says. On the TI 555 Rev. C data sheet, what is the modulation input for the PWM circuit? Also, can I round the resistor and cap. to 10k and .022uf, respectively?
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1answer
85 views

PWM understanding

I am giving PWM to a MOSFET (50% duty). It switches about 8.5V to be fed to a phase of a motor. There are 3 such phases. Now, I am looking at voltage measured from these phases as well. I have ...