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Timers & Counter Circuits
Designed by David A. Johnson, P.E.
Last Updated on:
Friday, April 25, 2008 04:24 AM
Master Category List - Dave's Circuits
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- CIRCUIT FORMS DIVIDE BY 1.5 COUNTER
Two inexpensive ICs divide a TTL clock signal by 1.5. By following the circuit with another flip/flop, you could also generate a divide by three function.
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- DARKROOM CAMERA SHUTTER TIMER
This circuit was designed to control a film exposure shutter for a darkroom. It has 8 time steps ranging from 0.35 seconds to 4 seconds. It is activated by a foot switch and draws power from
an external 12 volt DC supply.
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- HONEYBEE COUNTER
I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive. The low power circuit uses a slotted opto-sensor to detect
the passing bees. The circuit advances an electronic counting module whenever a honeybee passes through the sensor. The device only counts the number of bees going through the sensor. A
different circuit would be needed to count the number of bees only going out or only coming into the hive.
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- LONG PERIOD COMPUTER WATCH DOG TIMER
This circuit uses a simple 4060 IC oscillator/timer which is reset periodically by a computer. Should the computer fail to send a pulse, the output changes state. The time can easily be set
from seconds to hours.
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- On/Off Flip/flop Circuit with Automatic Timeout
This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time. With the components shown, the
output will stay on for only about 20 seconds.
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More Times & Counter Circuits
Master Category List - Dave's Circuits
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