Ultra Low Current 3v LED Flasher #3  -  This circuit takes advantage of a tiny LMC7215 low current draw voltage comparator from National Semiconductor and a super efficient green LED from King Bright. The 3v powered circuit forms a classic pulse generator circuit, which drives the LED. The pulse width is set at about 20ms, the pulse rate is about 0. 5Hz and the peak LED current is only 100ua . . . [Circuit by David Johnson P.E.,  02/27/11]

Ultra Low Power LED Flasher  -  The efficiency of some newer LEDs is amazing. Some of the latest green LEDs can launch blinding light with just one milliamp of current. I take advantage of one of these newer devices in the circuit below. The flashing circuit uses a classic multivibrator . . . [Hobby Circuit designed by Dave Johnson P.E.,  12/21/08]

UltraLow Distortion IF Amplifier/ ADC Driver with Digitally Controlled Gain  -   LT5514. . .  [Linear Technology]

UltraLow Power, 18-Bit, Differential PulSAR ADC Driver   -  A PC with Windows® XP or Windows 7 equipped with an USB port was used to run the PulSAR evaluation software. , Getting Started The software was installed as described at www. analog. com/EVAL-CED1Z , and www. analog. com/AD7982_adc_EVAL-CED1Z The PulSAR evaluation software, which is LabVIEW® based, was used to control the Audio Precision input signals and also to monitor the ADC inputs and output. The software allows the collection and processing of INL, DNL, and FFT data as shown in Figure 2, Figure 3, and Figure 4. . . .  [Analog Devices-Circuits from the Lab]  

Ultralow-cost, two-digit counter features feW components  -  08/17/06  EDN Design Idea   Two seven-segment displays and one microprocessor count from zero to 99. . .  [by Noureddine Benabadji, University of Sciences and Technology, Oran, Algeria]

unipolar stepper motor driver (only uses power when it makes a step)  -  This circuit is based on the UNIPOLAR stepper motor. The main feature of this circuit is low power consumption in the motor circuit. This is achieved by only turning on the individual outputs of the driver for 1/10th of a second for each step the motor makes. . .  [from Rob Paisley's Model Train web site]

Universal Input TRIAC Dimmable 4W LED Driver  -  The LT3799 is an isolated flyback controller with power factor correction specifically designed for driving LEDs. The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler. A strong gate driver is included to drive an external high voltage MOSFET. Utilizing an onboard multiplier, the LT3799 typically achieves power factors of 0. 97. . .  [Linear Technology App Note - , Jun 21, 2010]

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.,  07/11/06]

Universal PWM Driver  -  PWM drivers are used in analysing, testing, installing and powering all kinds of electronic and electrical devices. We have published a few designs in Elektor over the years: here we present a ‘de luxe’ version. must register on this site. . .  [Published in Elecktor July/Augu, 2010]

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.,  06/22/08]

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.,  03/22/09]

Use a CFL ballast to drive LEDs  -  04/26/07  EDN Design Idea   A CFL ballast can drive a string of as many as 64 LEDs. . .  [by Christian Rausch, Unterhaching, Germany]

Using All four Amplifiers of the LT1397 to Drive Large zCapacitive Loads  -  Four paralleled Amplifiers increase load capacitor current drive capability. A small ballast resistor at each output increases isolates the effects of each Amplifier's different output offset. . . .   [Linear Technology App Note - , Jun 29th 2012]

VCOM adjustment uses any logic-supply voltage  -  09/30/04 EDN Design Idea   All TFT (thin-film-transistor] LCD panels require at least one appropriately tuned VCOM signal to provide a reference point for the panel’s backplane. The exact value of VCOM varies.  Page includes several designs. Scroll to find t. . .  [by Peter Khairolomour and Alan Li, Analog Devices, San Jose, CA]

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 1.5volt 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.,  06/03/00]

Video Design Idea:  LED senses and displays ambient light intensity  -  09/05/07  EDN Design Idea   Explains how an LED can double as a photosensor and a visual indicator of ambient-light intensity. . .  [by Dhananjay V Gadre of India's Netaji Subhas Institute of Technology]

Video Design Idea: LED senses and displays ambient light intensity  -  09/05/07  EDN Design Idea   Explains how an LED can double as a photosensor and a visual indicator of ambient-light intensity. . .  [by Dhananjay V Gadre of India's Netaji Subhas Institute of Technology]

Video Design Idea: Microcontroller drives 20 LEDs  -  09/27/07  EDN Design Idea   Details and demonstrates the use of "Charlieplexing" to drive 20 LEDs using six available I/O pins on an 8-pin microcontroller. . .  [by Dhananjay V Gadre of the Netaji Subhas Institute of Technology in New Delhi, India]

Visible Laser Driver Has Digitally Controlled Power Modulation  -  App Note - / 228 / Mar-10. . .  [Maxim Integrated]

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.,  07/09/06]

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.,  03/22/99]

Voltage-to-current converter drives white LEDs  -  06/27/02  EDN Design Idea   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. . .  [by Susanne Nell, Breitenfurt, Austria]  

Voltage-To-Current Converter Makes A Flexible Current Reference  -  09/18/03  EDN Design Idea   The voltage-to-current converter in Figure 1 can both source and sink current. The circuit is flexible than some traditional current references that require different topologies for current sourcing and sinking. Also, you can easily. . .  [by Art Kay, Texas Instruments, Tucson, AZ]

Wall Clock Governor Driver  -  These were common before the advent of quartz controlled stepping motor clocks. Here is a reverse engineered diagram of this very typical circuit. . . .  [Reverse engineered schematic by Stepan Novotill]

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