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Twi-Light using White Leds - This sunlight-controlled lamp uses a light-dependent resistor (LDR) as the sunlight sensor and a total of 25 high-brightness white LEDs. Separate resistors are connected in series with each row of the...__ Electronics Projects for You
Two LEDs Perform Rudimentary Spectral Analysis - 09/01/94 EDN Design Ideas: A pair of LEDs having different wavelengths can supply the stimulus for a rudimentary spectral analysis during quality-control sorting operations. By measuring the reflectance of each LED, the circuit in Fig 1 can provide information about the spectral response of the object under test. The circuit's Design by Peter Bojilov, Isomatik Sortex Ltd, Pazardjik, Bulgaria
Ultra Low Power Detects Clear Fluid - Using an ultra low power technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing. it can be used for fluid level control and monitoring . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2005
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 Color Film Negative to Make an Optical Filter - This isn’t an electronic circuit but the file shows the curve for an optical filter made from exposed color film. The material blocks most visible light but is very transparent to 880nM infrared light. Kodak 100ASA is exposed to "cool white" fluorescent light for about 5 seconds . . . Hobby Circuit designed by Dave Johnson P.E.-January, 1998
Use LEDs as Photodiodes - 11/18/10 EDN Design Ideas: Ambient light changes an LEDs 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
Variable Isolated AC Voltage Spans 0VAC to 280Vac - I designed and built this circuit about 25 years ago. it came in handy for many projects that were powered from 120 VAC, 240 VAC and 277 VAC. it provides complete isolation from the power line. it uses two 1:1 isolation transformers that are wired in parallel. . . Circuit by Dave Johnson P.E.-July, 2000
Video Design Idea: LED senses & displays Ambient light intensity - 09/05/07 EDN-Video Design ideas - Explains 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
Water Pump controlled by Solar Power - A Discover Circuits visitor had a problem. He needed a simple on/off controller for his solar powered water pump. His system used two 12v 50 watt solar panels wired in series. The power from the solar panels drove a submerged water pump. However, during . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2010
Xenon Flash Receiver-Pg2 - This is Page 2 of the receiver circuit AiR TRANSPARENCY MONiTOR, XENON FLASH RECEiVER . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
Xenon Lamp Flash Detector Amplifier - This circuit has a very low standby current requirement yet has very high sensitivity toward the light flashes from a xenon lamp. When connected to a flip/flop it can serve as an on on/off Controller. . . Circuit by David A. Johnson P.E.-December, 2004
Light Detector, Monitor, Sensor and Optical Detector, Monitor, SensorPage E
Safety Light - My 1200 square foot metal shop only has one small entrance door and no skylights. if the lights are turn off while inside, there is not enough light to safely find the door to exit the building. On a couple occasions, while I was quietly working at my test bench, my wife would walk into the shop, grab a garden tool and rush back out, turning off the lights and closing the door without thinking . . . Hobby Circuit designed by David Johnson P.E.-November, 2004
Shop Safety Light - My 1200 square foot metal shop only has one small entrance door and no skylights. if the lights are turn off while inside, there is not enough light to safely find the door to exit the building. On a couple occasions, while I was quietly working at my test bench, my wife would walk into the shop, grab a garden tool and rush back out, turning off the lights and closing the door without thinking . . . Hobby Circuit designed by Dave Johnson P.E.-November, 2004 |
