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D - Flip-Flop Made With A LM556 Timer - Uses the LM555 timer or
its cousins with other letter prefixes. There can be minor differences
between 555 timer IC's from different manufacturers but they all should be
useable for any circuit. Designed for Model Trains…. [from Rob
Paisley's Model Train web site] |
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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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DCC Zero Stretching Simulator (LM555) - This circuit is designed
to simulate the 'Zero Stretching' function of Digital Command Control
systems used by model railroads. This circuit was used drive the booster
while testing the operation of block occupancy detectors and DCC signal
failure circuits while in the zero stretching mode.... [from Rob Paisley's
Model Train web site] |
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Delayed Re-Triggering - Uses the LM555 timer or its cousins with other
letter prefixes. There can be minor differences between 555 timer IC's from different
manufacturers but they all should be useable for any circuit. Designed for
Model Trains…. [from Rob Paisley's Model Train web site] |
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Dice - Press the push switch to 'throw' the dice: this makes the circuit
rapidly cycle through the dice numbers so that an effectively random dice number is
displayed by the LEDs when the push switch is released.… [Designed by John Hewes] |
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Driving A Bi-Coloured LED - Some 3-leaded LEDs produce red and green.
This circuit alternately flashes a red/green bi-coloured LED |
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Driving A Relay - The 555 will activate a relay. When pins 2 and 6 are
connected as an input, the chip requires only about 1uA to activate the output.
This is equivalent to a gain of about 200,000,000 (200 million) and represents about 4
stages of amplification via transistors.... |
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Driving Loads Of Greater Than 15 Volts - Uses the LM555 timer or its cousins
with other letter prefixes. There can be minor differences between 555 timer IC's from
different manufacturers but they all should be useable for any circuit.
Designed for Model Trains…. [from Rob Paisley's Model Train web site] |
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Driving White LEDs - The 555 is capable of sinking and sourcing up to 200mA,
but it gets very hot when doing this on a 12v supply. The following circuit
shows the maximum number of white LEDs that can be realistically driven from a 555 and
we have limited the total current to about 130mA as each LED is designed to pass about
17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means
only 3 LEDs can be placed in series. |
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Dummy Alarm - This project makes a superbright LED flash briefly once every
5 seconds to imitate the indicator light of a real alarm. The circuit is designed to
use very little current to prolong battery life so that it can be left on permanently.
This is a simple project, ideal for a beginner.... [Designed by John Hewes] |
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Eight LEDs Random Flasher - This project uses a 4026 counter and display
driver IC to flash eight LEDs in an apparently random manner. It can be used to create
a display of your choice.… [Designed by John Hewes] |
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Electronic Time Constant Control - Uses the LM555 timer or its cousins with
other letter prefixes. There can be minor differences between 555 timer IC's from
different manufacturers but they all should be useable for any circuit.
Designed for Model Trains…. [from Rob Paisley's Model Train web site] |
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