praveen @ circuitstoday.com writes:
In this article we explain how to do PWM (Pulse Width Modulation) control using arduino. If you are new to electronics, we have a detailed article explaining pulse width modulation. We have explained PWM in this tutorial using 2 examples which will help you learn how to control LED brightness using PWM and how to control DC motor speed using PWM.
PWM Control using Arduino – Learn to Control DC Motor Speed and LED Brightness - [Link]
by Susan Nordyk:
The LT8471, a dual PWM DC/DC converter from Linear Technology, employs two internal 2-A, 50-V switches and an additional 500-mA switch to facilitate step-down, step-up, and inverting conversions. Each 2-A channel can be independently configured as a buck, boost, SEPIC, flyback, Zeta, or inverting converter.
This broad range of topologies and output configurations makes the LT8471 useful for a wide range of industrial and automotive applications. The converter operates from an input voltage of 2.6 V to 50 V, allowing it to be used with input sources ranging from single-cell lithium-ion to automotive batteries.
The LT8471 is capable of generating both positive and negative outputs. Its switching frequency is programmable and synchronizable from 100 kHz to 2 MHz. The device’s 50-V switches achieve overall efficiencies of up to 85% for buck and inverting applications. Operating from a 6-V to 32-V input, the LT8471 delivers up to 1.5 A at 5 V and 650 mA at –5 V.
Housed in a 20-lead, thermally enhanced TSSOP, the LT8471 costs $3.75 each in lots of 1000 units. An industrial-temperature version is priced at $4.13 in like quantities. Both versions are available from stock.
Multiple-topology DC/DC converter integrates dual 2-A switches - [Link]
A solar charge controller regulates the voltage and current coming from your solar panels which is placed between a solar panel and a battery .It is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar panel rises, the charge controller regulates the charge to the batteries preventing any over charging.
Arduino Solar Charge Controller (PWM) - [Link]
ajoyraman @ instructables.com writes:
PC sound cards form a readily available Signal Generator for testing electronic circuits. The utility of these signal generators is limited because the outputs are AC coupled and limited to ±2V.
Taking advantage of the two channels provided by the sound card this Instructable shows a scheme which uses one channel to output the Sin/Square/Triangle waveform with a fixed gain, while setting up a 441 Hz PWM square wave on the second channel. This PWM waveform is converted to ±8V averaged and summed with the first channel to provide a DC offset controllable by the duty-cycle setting.
PC Sound Card Signal Generator Interface - [Link]
This relatively simple circuit uses a 6-V DC supply with a PWM current-source configuration to provide efficient, adjustable dimming of a white LED over a wide range, needed to accommodate the unique lighting needs of an optical microscope over its magnification range from 40× to 1000×. by James Campbell
When the built-in incandescent light source of my venerable Olympus microscope failed after many years of use, I decided to design a reliable modern replacement. A 1-W white LED (SEOUL X42182, 350 mA max, Vf = 3.25 V) was the obvious choice to provide high brightness and full-spectrum light without the heat of incandescent or xenon arc lamps. The microscope lamp brightness needs to be adjustable, however, to accommodate the different objective lenses, which offer magnifications from 40× to 1000×.
Current Source For LED Microscope Illuminator Provides Full-Spectrum Light - [Link]
Marios Andreopoulos writes:
A few days ago I wrote a blog post about Arduino and EMI. By using fast PWM and a plain breadboard wire, I was able to detect electromagnetic interference using a usb TV tuner, with its antenna near my circuit. Not only that, but by manipulating duty cycle to create a primitive form of amplitude modulation, I was able to transfer through EMI a very simple audible signal (few notes of one of the most famous riffs) in many frequencies and up to 1.76GHz
Fast PWM and Electromagnetic Interference - [Link]
LED drivers are electrical devices that regulate the power of LEDs. What makes them different from conventional power supplies is their ability to respond to the ever-changing need of LEDs in a circuit by supplying a constant amount of power as electrical properties change with temperature.
The PCA9622 is an I2C-bus controlled 16-bit LED driver optimized for voltage switch dimming and blinking 100 mA Red/Green/Blue/Amber (RGBA) LEDs. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller that operates at 97 kHz with a duty cycle that is adjustable from 0 % to 99.6 % to allow the LED to be set to a specific brightness value. An additional 8-bit resolution (256 steps) group PWM controller has a fixed frequency of 190 Hz and an adjustable frequency between 24 Hz to once every 10.73 seconds with a duty cycle that is adjustable from 0 % to 99.6 % that is used to either dim or blink all LEDs with the same value.
These LED drivers are based on system-centric, mixed-signal LED driver technology for backlighting and solid-state lighting (SSL) applications. This broad-based and rapidly growing market includes LCD TVs, PC monitors, specialty panels (industrial, military, medical, avionics, etc.) and general illumination for the commercial, residential, industrial and government market segments. LED drivers utilize a proprietary and patented combination of analog and digital circuit techniques and power control schemes.
- PCA9622 I2C-bus controlled 16-bit LED driver
- 2C-BUS/SMBus MASTER
- Resistor 10kΩ ( 27 units)
- LED (88 units)
- Voltage Source 40Vdc
- Voltage Source 5Vdc
I2C Bus Controlled LED Drivers for backlighting and SSL applications – [Link]
“Click And See “ is a system supporting the search of electronic components. The idea came during yesterday’s shopping in one of the electronics stores , cabinets with electronic components fill the entire wall. When buying several different components , the seller needs time to find them first in your computer , then in the appropriate bins , and the queue of customers getting longer … To facilitate this, I designed a simple , wireless and easy to expand the system to highlight the drawer of the element that want to buy .
more info here: CLICK_AND_SEE_ENG
Click and See – find electronics parts with a click - [Link]
Nick Leijenhorst build a 555 PWM circuit to dim his room LED lighting. He writes:
I wanted to dim my room LED lighting with a potentiometer, and decided on creating a solution from scratch to make it more fun and educative. I decided to go with the fairly well-known 555 PWM circuit. To decrease size and for learning purposes I decided on using surface-mount components for the first time. The reason I wanted to make this 555 PWM circuit is actually just to see if I could solder SMD components on home-etched PCB’s, and to see how hard it actually is.
Surface-mount 555 PWM circuit - [Link]