Universal LED Flasher - This low power LED flasher circuit draws about 100ua from any DC power supply ranging from 3 volts to 24 volts. The 1.0Hz 10ms LED pulsed current is held to a constant 10ma. . . Circuit by David A. Johnson P.E.-July, 2006 Universal-3v-LED-Flasher - The circuit below will flash any LED color with fixed current pulses powered by a 3v battery. It uses a charge pump approach, which routes a constant current pulse through the LED, regardless of the LED voltage requirement. Using this approach, white and. . . Circuit by David Johnson P.E.-June, 2008
Up / Down Digital Counter with 7 Segment LED Displays - REVISED Really as Simple as you can get and has 4 Displays __ Designed by G.L. Chemelec
Up/Down Ramping Light Pushbutton Control - There are times when you want a lamp to gradually change from dark to light and from light to dark, with each push of a pushbutton switch. The circuit below performs this control function using a flip/flop and a classic pulse width modulation or PWM. . . Circuit by David Johnson P.E.-March, 2009
USB LED Light - A simply and easy-to-make circuit, useful when working with the computer at night. (6/08/2006) __ Designed by Jose Pino
USB LED LoA - D - The board supports driving two separate tri-color LEDs. More can be setup inline if desired. Currently the software only uses the second LED and its color represents the CPU load of the system in real-time. Blue for idle and gradients light blue, green, yellow, orange, and finally red indicating heavy CPU utilization. If the system fails to respond, the LED begins flashing RED to indicate a lack of communication from the software. This lets you easily identify a crashed machine in a rack for example.
USB LED Night Light - A typical USB LED bulb shown in Fig.1 is a 5V, 5W USB-powered solid-state lamp. At the heart of this light bulb is a circular aluminium PCB made with a...__ Electronics Projects for You
Use a CFL ballast to drive LEDs - 04/26/07 EDN-Design Ideas A CFL ballast can drive a string of as many as 64 LEDs Design by Christian Rausch, Unterhaching, Germany
Use an LED Matrix Horizontally - 02/16/12 EDN-Design Ideas Using one 5×7 LED matrix horizontally instead of vertically allows the display of two characters instead of one. LEDs provide a convenient way to electronically display information. Although the seven-segment LED display, arranged in the form of the digit 8, is common, it does not allow the display of some alphanumeric characters. A 5×7 LED matrix allows the display of all ASCII characters, as well as graphics shapes. LEDs provide a convenient way to electronically display information. Although the seven-segment LED display, arranged in the form of the digit 8, is common, it does not allow the display of some alphanumeric characters. A 5×7 LED matrix allows the display of all ASCII characters, as well as graphics shapes. The circuit in this Design Idea shows an unconventional way to use a 5×7 LED matrix.
__ Circuit Design by Benabadji Noureddine
Use an LED to Sense & Emit Light - 14-May-09 EDN-Design Ideas LEDs in portable devices often show power status, battery status, or Bluetooth-connection activity. LEDs can be major factors in determining battery life because their intensity is directly proportional to power drain Design by Rafael Camarota, Altera Corp, San Jose, CA
Use LEDs as Photodiodes - 11/18/10 EDN-Design Ideas Ambient light changes an LED's resistance, making it act like a photodiode. [Design Idea by Raju R Baddi, Raman Research Institute, Bangalore, India Design by Raju R Baddi, Raman Research Institute, Bangalore, India
Use Simple Circuit LED for near-IR light - 09/01/98 EDN-Design Ideas NOTE
: File has many circuits, scroll down. You can successfully use LEDs as sources of near-infrared light. However, when you need a source of light with precisely controlled power, a feedback loop is necessary to compensate for the temporal and thermal changes of the LED parameters. Standard LED types come with neither these monitoring detectors nor an external monitoring photodiode to detect part of the emitted light and generate a feedback signal. The situation calls for some mechanical fixture to mount the photodiode. Design by Lukasz Sliwczynski, Marcin Lipinski, Institute of Electronics, Krakow, Poland
Using the LM317T with LED Lighting - Use an LM317T to regulate the current in LED lighting projects. __ Designed by REUK-Renewable Energy UK website
UV LED Flashlight Driver - The rapid development of LED technology is also reflected in the production of integrated drivers, often called LED Drivers. The market is plentiful lots of different integrated circuits for this purpose. There are circuits for generating serial or parallel cascades LED Step-Up and Step-Down Convertor, charge pumps. But when you need them to realize any involvement, and usually encounter unexpected problems. Many drivers LED (LED Drivers) is designed for a specific range of consumer electronics and often lacks the characteristics required of us. __ Designed by © Pavel Janko
Valentine Heart - 18 LEDs flash at three different rates and you can use these to create an eye-catching Valentine Heart for that special person! A template for the heart shape can be downloaded. The circuit is kept simple (and low cost) by using the 4060B IC which is a counter and oscillator (clock) in one package. The circuit requires a 9V supply, such as a PP3 battery __ Designed by John Hewes
Versatile LED Display - This circuit uses an erasable programmable read-only memory (EPROM) to display various light patterns on LEDs. Since bicolour LEDs (comprising green and red LEDs) have been used, display is possible in...__ Electronics Projects for You
Version a of 1.5v LED Flasher - To squeeze even more energy from a alkaline battery cell, this circuit adds two transistors to a circuit similar to the above design to boost the efficiency. A small 1.5 volt alkaline N cell should flash the LED for a full year. It too uses a "charge pump" technique to provide a LED the needed voltage. . . Circuit by David A. Johnson P.E.-June, 2000
Video Design Idea: Buck regulator controls white LED with optical feedback - 10/25/07 EDN-Video Design IdeasBy using optical feedback, you can stabilize the output level of a high-intensity LED Design by Dhananjay V Gadre, Netaji Subhas Institute of Technology, New Delhi, India
Video Design Idea: LED senses & displays Ambient light intensity - 09/05/07 EDN-Video Design IdeasExplains how an LED can double as a photosensor and a visual indicator of ambient-light intensity Design by Dhananjay V Gadre of India's Netaji Subhas Institute of Technology
Voltage Monitor - This voltage monitor circuit is based on an Elektor design with a 555 timer IC in the book 302 Circuits, which uses two LEDs (red and green) to indicate whether the voltage is within range. must register on this site __ Designed by Published in Elecktor July/Aug, 2013
Voltage Monitor - When the input voltage is 0 the LED glows. The LED stops glowing when the voltage rises to the level determined by R2. Reverse + and, pins to reverse operating mode. To set voltage at which LED goes __ Contact: IQ Technologies
Voltage Monitor for a 9v Battery - Nine voltage batteries are used in a wide variety of electronic devices. But, you often don’t know when it is time to change the battery until the device stops operating. The hobby circuit below provides a visual indication when the battery needs to be . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
Voltage to Frequency Converter + 1us LED Pulse Driver - This circuit receives the signal from the above amplifier and launches powerful 1uS infrared light pulses from a low cost LED that are frequency modulated by the audio information. The 10KHz center frequency of the pulse stream is low enough so a standard. . . Circuit by Dave Johnson P.E.-March, 1999
Voltage-to-current converter drives white LEDs - 06/27/02 EDN-Design Ideas Reset generator uses "fleapower" = You sometimes need to drive a white LED from one 1.5V battery. Unfortunately, the forward voltage of a white LED is 3 to 4V. So, you would need a DC/DC converter to drive the LED from one battery. Using the simple circuit in Figure 1, you can drive one white LED or two series-connected green LEDs, using only a few components Design by Susanne Nell, Breitenfurt, Austria |