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Timers and Counters Circuits,
Page 2a Timers & Counters:
#-ANext
B-EPrevious B-EF-LM-S T-Z Last Updated on:
Friday, March 12, 2010 12:07 PM
Circuits Designed by Dave Johnson, P.E. :
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.
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.
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
Delay line has Wide duty cycle range: 06/27/02 EDN Design Ideas /
(added 1/05) Today's digital delay lines can process pulses no shorter than
their delay times, and that restriction confines the devices to applications in
which the duty cycle remains near 50%. A limited range of available delays (2 to
100 nsec per tap) further limits their use. Longer delay is available with
one-shot multivibrators of standard digital-logic families, but those devices do
not retain duty-c......
Deoderizer Fan Pushbutton Timer : For use in a bathroom or car. I've
seen similar circuits used in plastic pot-pourri containers. (added 2/05)
Design Low duty cycle timer circuits: 08/22/02 EDN Design Ideas /
(added 1/05) Designing astable circuits using the industry-standard 555
timer is a straightforward process when duty cycles are 50% or greater. However,
you must overcome the many pitfalls of low-duty-cycle circuits to arrive at a
desired result. Using only ideal components eases the design, but the components
themselves are hard to obtain....
Digital Clock with Timer and Solar Panel Regulator: This is a
combination digital clock timer and solar panel charge controller used to maintain
a deep cycle battery from a solar panel. The timer output is used to control a 12
volt load for a 32.... (added 05/07)
Digital Timer Light Switch : Typical circuit representative of those
used in most light switch type digital timers. The timer module is normally a PIC
or custom chip, and it syncs to the AC line so that a trigger pulse can be
supplied at the right moment. (added 2/05)
Extend the timing capabilities of a PC: 01/10/02 EDN Design Ideas
/ (added 1/05) Even when you use the internal timing registers and
under DOS, a PC cannot easily measure time intervals with better time resolution
than a millisecond. Measuring long intervals with even this precision is a waste
of many CPU cycles. A microcontroller is well-suited for this task; you can easily
integrate a PIC with a PC to extend the timing precision into the microsecond
range for perio... ...