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Dark Activated 12v Power Supply Switch - Using an inexpensive
phototransistor, this circuit switches 12v to 24v power to a load,
whenever the sun goes down.…. [Designed by David A. Johnson] |
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Dark activated switch - started this project with the idea to
build a simple single-ended tube amplifier. I didn't have any experience
with the construction of tube amps so I was looking for a beginner's
project. Such a project should be simple (for easy debugging) and it
should …(electroninc design added 04/05/06) |
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Dark Activated Switch - This circuit will activate a relay when
light falls to a preset level. Light level can be adjusted with VR1 and
the relay contacts may be used to operate an external light or buzzer.…
[Andy Collison] |
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Dark Detector - When the level of light on the photo-cell
decreases, the 555 is activated. Photo-cells (Photo-resistors) have a wide
range of specifications. Some cells go down to 100R in full sunlight while
others only go down to 1k. Some have a HIGH resistance of between 1M and
others are 10M in total darkness. For this circuit, the LOW resistance
(the resistance in sunlight) is the critical value..... |
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Dark Sensitive Switch - Dark Sensitive Switch is a simple project which
operates a relay when the light falling on the LDR goes below a set point.…. [Site is
under construction right now] |
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Dark/Light Activated Relay - The potmeter adjust the trigger 'on' level.
The diode in the diagram shows to be 1N914. This is ok if you have a light-duty relay,
also the 1N914 is a signal diode so actually does not qualify. Use a 1N4001
(Tony van Roon's or better) instead. A couple of substitutes for the 2N2222
transistor are: NTE123A, ECG123A, PN100, etc..... [Tony van Roon's circuit] |
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Dark-activated 230V Lamp - Compact circuitry using small-size parts only.
Can be wired in parallel to existing switches. (added 4/05) |
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Dark-activated LED or Lamp Flasher - This circuit adopts the rather unusual
Bowes/White emitter coupled multivibrator circuit. The oscillation frequency is about
1Hz and is set by C1 value…..(electronic design added 6/07) |
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Dark-activated switch needs only three components - 23-Jul-09 Issue of EDN
Build a dark-activated switch with only a triac, a photocell, and a resistor.....
[Design Idea by Abel Raynus, Armitron International, Malden, MA] |
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Dark-Detecting LED Circuit - Here's a simple problem: "How do you make an
LED turn on when it gets dark?" You might call it the "nightlight problem," but the
same sort of question comes up in a lot of familiar situations-- emergency lights,
street lights, silly computer keyboard backlights, and the list goes on. Solutions?
Lots. The time-honored tradition is to use a circuit with a CdS photoresistor,
sometimes called a photocell or LDR, for "light-dependent resistor.".….(design added
11/08) |
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DAS1 10A/12V Dark Activated Switch - The DAS1 is a combination manual switch
and automatic dark-activated switch. It is designed to control up to 10 amps of 12V
lights. A pair of high-intensity white LEDs are included in the circuit for built-in
lighting. The circuit includes a low voltage disconnect circuit that prevents
excessive battery discharge on battery operated systems..... [G. Forrest Cook] |
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Day/ Night/ 24 Hour Select Sensor - (circuit / schematic design added 6/06)
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Digitally control room light intensity - 11-Nov-04 Issue of EDN Many
people favor different light and temperature settings for different rooms depending
upon their mood or whether they are working or relaxing. The circuit in Figure 1
controls the intensity of the artificial light in a room and monitors the temperature
of two zones. The two main circuit blocks are the PIC16C67 master controller and the
ADT7516 temperature-sensor interface, which includes a..... [Design Idea by Donal
McNamara and Kieran Kelly, Analog Devices, Limerick, Ireland] |
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Electronic Night Light - This circuit for an electronic night light was
submitted by Adam from Canada. I have provided the notes [Andy Collison's design] |
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Feedback circuit enhances phototransistor's linear operation - 12-Oct-06
Issue of EDN Bias-current compensation reduces ambient-light saturation
effects..... [Design Idea by JC Ferrer and A GarrigĂłs, University Miguel Hernandez,
Elche, Spain; Edited by Brad Thompson and Fran Granville] |
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IR Proximity Detector - The circuits on this page are for an Infrared
Proximity Detector using the Vishay Electronics TSOP4830 "IR Receiver Modules for
Remote Control Systems"….Scroll down to view all the circuits…. [from Rob Paisley's
Model Train web site] |
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