Pulse-width modulation, is varying the duty cycle of a rectangle wave, usually with a constant frequency.
-8
votes
0answers
54 views
Crystal oscillator “voltage control” pin usage [closed]
What does "voltage control" mean for a crystal oscillator?
For example where a crystal oscillator marked "40 Mhz" has a control pin.
Can I use PWM to control it?
0
votes
1answer
19 views
How to Control SM1 Inverter Drive Frequency with Arduino?
I am back at trying to control the frequency of an SM1 AC inverter drive due to the fact that I never got it going the first time. However, this time I would like to use an Arduino. The manual for the ...
2
votes
1answer
45 views
Raspberry Pi: driving Servo with PWM
I'm experimenting with a small servo motor with the raspberry pi using PWM (pulse-width modulation). My understanding is that the servo should respond to different length of pulse. I should be seeing ...
1
vote
1answer
59 views
Topology of solar PWM charger
I am looking into the design of the most simple (yet functional) PWM solar chargers for lead acid batteries. (Numerous examples can be found on Ebay for about 10 bucks.)
I have a hunch that they ...
5
votes
1answer
72 views
DC Motor Overvoltage Operation
I am new to PWM control. Is it advisable to operate a motor at higher than rated voltage with the "PWM average voltage" more than the nominal voltage specified in the datasheets? After some ...
1
vote
1answer
85 views
Transmitting power and PWM signal through the same cable
I am working on an Arduino based project, which required to supply 24VDC at 2A and 3 PWM outputs from the main board to the other board. The 24VDC is for powering the LEDs, and PWMs are for dimming ...
4
votes
1answer
62 views
Reducing LED PWM Noise: Which is the best option?
Driving an LED with a microcontroller should be easy. But when looking into noise, things can get complex...
As an instantaneous voltage indicator used in a variable power supply (which will be used ...
2
votes
3answers
114 views
PWM Control with MOSFET switch
I plan on using a 555 timer for a PWM signal (variable with a potentiometer) and a gate driver to use a MOSFET as a switch. Essentially, I am trying to take a +300V rail and "step" it down using the ...
0
votes
0answers
35 views
PIC32 PWM minimal example
I am having trouble getting a simple PWM output to work at all on a PIC32MX775F512H. Looking online, this seems to be all I need to get something working:
...
0
votes
1answer
47 views
PWM Motor Speed Control
I recently bought one of these:
When i hooked it up to my 24v power supply and a voltmeter, it was either 0 or 24v with the POT. Nowhere in between. Why is this? Is it becasue this is a PWM device ...
3
votes
1answer
82 views
Strange behavior from variable-gain amplifier
Sorry, this might not go anywhere. My first SE question, though, on any site.
I've built at least three distinct audio amplifiers with the TDA7056B, which is a really great amp. It takes a voltage ...
2
votes
1answer
79 views
Servo position with no pulse
I am using a PIC 16F884 to run 2 motors and 2 servos. The motors are using the onboard PWM module, and I am bit banging PWM for the servos on Timer 2.
With only one servo being controlled, it ...
4
votes
3answers
80 views
Arduino AnalogWrite and its frequency and effectiveness
Reading about the arduino analogWrite function I have come to understand that it uses PWM for the variable DC voltage. (by controlling the width of the pulse)
However how do we control the frequency ...
1
vote
2answers
70 views
Simulate tach signal of PWM fan
I have a power supply that uses a PWM fan with 4 wires.
Wires: 12V (red), GND (black), PWM Control (brown), TACH Sig (white)
The fan speed is controlled by the PWM control wire (brown). Fan speed is ...
2
votes
1answer
77 views
Reversing a .5-4.5V analog sensor output to 5V-0V
I have a pulse width modulation (PWM) control board that uses a 0-5V input via a potentiometer to control a DC motor speed. As I understand how this works, the potentiometer goes from 0% PWM at 0V to ...
1
vote
1answer
93 views
how to control constant current led driver output with pwm?
i want to control brightness of led series with constant current power supply.
but when i connect the power supply output to pwm controller and led series, i cant control the brightness because power ...
1
vote
1answer
42 views
PWM npn sinking signal
I have a stepper motor(with STR2 Step Motor Drive) which needs npn sinking signal to operate. dsPIC33EP512mu810 is capable of generating high resolution pwm. However, the PWM signal can only turn on a ...
3
votes
1answer
180 views
Criteria behind selecting pwm frequency for speed control of a dc motor?
I'm working on a speed control circuit for a brushed dc motor (24v, 500rpm, 2A, 4kgcm).
The main components that I plan to use are PIC16f873, 4n25 optocoupler, IRFZ44N MOSFET, BY 500 - 800 diode(for ...
4
votes
3answers
166 views
Driving Permanent Magnet DC Motor via PWM
SUMMARY:
I am currently trying to finish up a DIY project I've been working on for a while: Building an electric potters wheel. I acquired a treadmill and salvaged quite a few good parts from it, and ...
3
votes
2answers
122 views
arduino pulse to transistor power maximum
Hello I want to get a confirmation that what I am doing is not going to fry my Arduino Mega.
The sketch I am using to send a pulse out on pin 8 to a 2n3055 that is switching 12 volts is this:
...
0
votes
1answer
50 views
Shifting between PWM options
I'm using a Freescale MC9S08DZ60 microcontroller, and Ive written the code for applying PWM on a specific pin.'This is an attempt for Breathing Effect of LED, a question i had already asked - LED ...
1
vote
0answers
38 views
Parallel, low noise motor driver design with L293D [duplicate]
I'm designing a very basic motor driver circuit for 12V DC brushed motors to be connected with my microcontroller. The motor needs to be driven in forward and reverse
My objective is to do that with ...
12
votes
1answer
260 views
Sine signal generation using PWM
We are unable to generate a sine signal properly using a MC68HC908GP32 microcontroller. PWM description begins in page 349. Clock frequency is 2.4MHz, while we have used 7 kHz PWM by using the ...
2
votes
2answers
172 views
Arduino PWM shield with npn transistors
I'm using a PWM shield (http://www.practicalmaker.com/products/arduino-shields/pwm-shield-assembled) which allows to extend the number of PWM pins for an Arduino.
In my project I'm using NPN TIP120 ...
0
votes
2answers
238 views
LED Breathing Effect
Please consider the following code:
for(;;)
{
int i=0;
TPM1C2VL =~ (i<<1); // Channel Value(Lower)Register.
TPM1C2VH +=TPM1C2VL;
}
ALTERED CODE
...
2
votes
1answer
101 views
Simplest design approach for PWM control with power MOSFET
I'm designing an application in which the current running into a load is controlled by PWM. A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
0
votes
2answers
81 views
PWM controller to meet EMI/EMC regulations
I'm designing an application in which the current running into a load is controlled by PWM.
A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
1
vote
2answers
117 views
Controlling a Servo with a TLC5940 (calculating PWM setting)
I'm trying to control a few servos and a bunch of RGB-LED from an arduino board. To do that I'm going to chain together a few TLC5940 chips. The issue I'm trying to resolve at the moment is what PWM ...
4
votes
2answers
28 views
Is it possible to remap the PWM output to other pins?
The Arduino Uno has PWM outputs on pins 11, 10, 9, 6, ...
10
votes
2answers
35 views
Why do some pins have `~` signs next to their numbers?
I was looking at my Arduino Uno and I noticed that symbol by digital pins 11, 10, 9, ...
-5
votes
1answer
95 views
How to multiplex leds using a microcontroller? [closed]
I saw this project online for a simple binary clock:
It's a very simple circuit. What I can't figure out, is how you can control each row separately.
The parts list is as follows:
1 - High ...
0
votes
1answer
32 views
What are fast and slow decay timings in the Allegro A3201 low voltage meter?
In the A3901 Low Voltage Meter Driver datasheet Figure 8 on pg. 10 shown below indicates what the output "IOUT 2/3-4" will look like given input "IN1/3 or IN2/4".
But Figure 8 does not mention ...
1
vote
1answer
125 views
Soft-Starter PWM Noise
I have developed a soft-starter for a project of mine. I am using an Arduino Uno to generate PWM to an OAC-5 relay that turns on and off the voltage across my bridge rectifier.
Here is a simple ...
0
votes
2answers
681 views
Arduino controlled PWM PC Fan
I am looking at getting 2 Evercool EC8015HH12BP 80x10mm (4-wire) PWM fans. However, i am looking at controlling the fan speed with the arduino via the PWM pins.
I found the following diagram that ...
1
vote
2answers
193 views
Apply PWM signal to PIN of a Microcontroller
I am using the MC9S08DZ60. I have been give a circuit diagram according to which i must program the micro-controller. I am using Code warrior with Processor Expert which allows me to initialize the ...
1
vote
3answers
259 views
Dimming multiplexed LEDs
I'm multiplexing 32 LEDs in a 4:8 configuration on an ATMega328 and am trying to dim them with what is probably a completely naive understanding of PWM. Note: I'm multiplexing them directly with 12 ...
1
vote
2answers
266 views
PWM Motor speed control using PIC; What mosfet to use
I have a 5V PIC16f877a controlling the speed of the motor 12V which has a power rating of 8W; the current will be around(600mA) am I correct?
The motor is basically a small water pump commonly used ...
5
votes
2answers
140 views
making a dc motor sing under load
I have a battery operated toothbrush that I want to generate notes with using PWM on the motor. The microcontroller used is an Arduino for testing and am able to get a bare motor to generate tones. I ...
2
votes
1answer
122 views
TLC59116F (i2c led driver) everything seems ok but LED doesn't work
I'm trying the LED driver TLC59116F with an arduino UNO R3. This IC is a i2c controllable LED driver with PWM and 16 outputs. The registers seem all loaded fine, here's a print of their contents:
...
0
votes
2answers
400 views
15V 3A dc motor PWM frequency setting
What is a suitable frequency for 15V/3A DC motor? Is there any effect on the motor when the frequency is changing? I am confused with this until now and the Internet shows a lot of theory that ...
2
votes
1answer
119 views
Is a low load resistor a big problem in low pass filter and amplifier circuit
I am going to use AVR's PWM output signal to pass through a low pass filter (maybe plus an amplifier). I found the speaker has a quite low resistance (8 ohms). I tried to simulate my schematic on ...
-2
votes
3answers
185 views
How do I calculate the required value for a pull-down resistor in a PWM circuit?
I'm using 74HC595 with SoftPWM to control some LED's.
When the 74HC595 is off, its outputting about 0.57v, enough to turn my LED's on somewhat.
How do I work out the value of the pull-down resistor ...
2
votes
1answer
115 views
PWM & NUD4001 LED driver
Today I tried to build a small circuit which basically consists of three NUD4001 LED driver, three n-Channel FETs and a RGB Power LED from SEOUL. I don't have the exact specs ready but the main specs ...
2
votes
1answer
144 views
Motor control with AVR
I am used to work with PICs, but I want to start using AVRs as well. One thing I like in the PICs is the EPWM (enhanced PWM) peripheral, in which you just set a couple of registers, and the PIC will ...
1
vote
1answer
107 views
AIC1863: How to use this MC to detect the presense of IR transmission?
I have build simple prototype on STM32 ARM Cortex microcontroller trying to understand the usage of AIC1863 IR Preamplifier for Remote Control System (see the handmade PCB on the breadboard).
MCU ...
2
votes
1answer
101 views
PWM drivers of Shift registers that are not open drain?
I am need of a 16 channel PWM Serial based LED driver, or serial in – parallel out shiftregister. I had been looking at TLC5940 and TLC59025 respectively.
But for my current set up the ouptuts ...
3
votes
1answer
66 views
What is the fixed-on interval with regards to stepper motors?
I am using a stepper drive board to control a stepper motor. It has settings for for fixed-on time when using the open-loop PWM control method.
According to the API description:
...
4
votes
3answers
235 views
Square wave -5 to +5 volt at 500 Hz
I need to make a square wave -5 to +5 V at approx. 500 Hz - with small current. I have 0 (ground) and +5 V and a PWM (a Waspmote with a ATmega1281 microcontroller). I think it would be possible to ...
1
vote
1answer
354 views
Arduino alternate PWM input method
I'm working on a rudimentary flight stabilization system for an airplane, which reads in 4 PWM inputs from an R/C receiver. The problem is, the pulseIn command is taking far too long to execute, so I ...
3
votes
3answers
236 views
What is the use of PWM over brushless control
I just saw this question How do I eliminate PWM noise when driving a fan? but cannot think of the reason why is doing PWM over brush-less control useful.
I am assuming people are trying to control ...
