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Timers and
Counters Circuits, Page 2 Timers & Counters: #-AB-EF-LM-S T-Z Last Updated on:
Monday, October 03, 2011 06:07 PM
Circuits Designed by Dave Johnson, P.E. :
Camera Shutter Time Measurement
while back I got an email from someone who needed a simple way to measure the speed
of a photographic camera. I thought about this and suggested the method below. It
relies on an oscilloscope and a cheap photodiode to measure the speed.....
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.
Garage Door Timer
The circuit below is designed to automatically close a garage door, if it was left
open for a long period of time. A reed relay and magnet combination sense when
the door is fully open. An ultra low power voltage comparator oscillator and
two 74HC4040 ICs are used to generate the time delay. A jumper or a switch can
be used to select a time of 30 minutes, one hour or two hours. The circuit
draws only about 2ua so a pair of AA alkaline cells would keep the unit running for
many years.
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
Basic Circuits For The LM555 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]
Bike Turning Signal - This circuit can be used to indicate left
and right turn on a motor-bike. Two identical circuits will be needed, one
for left and one for right….
Bipolar LED Driver - 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]
Bi-Polar LED Driver - Some 2-leaded LEDs produce red and green.
These are called Bi-polar LEDs. This circuit alternately flashes a
red/green bi-polar LED
Car Tachometer - A 555 is configured as a monostable or one shot
in this project. The period of the 555 is determined by the 47k and the
capacitor from pin 6 to ground (100n). Time "T" = 1.1 RC or 1.1
X 50,000 X 0.1 X10 -6 = 0.0055 or 5.5 mS (milli-seconds)....
Camera Shutter Time Measurement
while back I got an email from someone who needed a simple way to measure the speed of
a photographic camera. I thought about this and suggested the method below. It
relies on an oscilloscope and a cheap photodiode to measure the speed.....[Circuit
of the Week designed by David Johnson]
Christmas Decoration - This project flashes 18 LEDs at three different rates
and you can use these to create a Christmas decoration of your choice. The circuit is
kept simple (and cheap!) by using the 4060B IC which is a counter and oscillator
(clock) in one package. The circuit requires a 9V supply, such as a PP3 battery....
[Designed by John Hewes]
Clark Zapper - This is the circuit for Dr. Hulda Clark's Zapper, designed in
2003. The frequency is approximately 30kHz positive offset square wave. It has a red
LED light that lights up when the unit is on. Perfect for regular zapping, extended
zapping and other Hulda Clark related experiments....
Continuity Tester - This circuit will detect low resistances and high
resistances to produce a tone from the speaker. It will detect up to 200k and
the circuit automatically turns off when the probes are not used.
Controlling Circuits For LM555 Timers - 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]
Convert Thermostat to 12v Timer Switch - Find out how to modify a battery
powered thermostat to be used as a 12 Volt DC timer switch…. [REUK - Renewable Energy
UK website]
Cross Canceling For Monostable Timers - 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]
