I wana to add something from my earlier experience.
you should use pulse mode trigering for turning on the triac that way
it can handle. say pulse train of 2kHz with 10% duty cycle will be
great. use some transister as 2N2222 to power up the triac
triggering...
as JIM said, EEPROM is not for that kind of circuitary. guess true, u
can always avoid this by a single decade counter chip with de-
mutiplxed output (10 seperate output changing state one by one) and
wire it for your desired sequence. why to use momory when U can build
this 3 or 4 bit memory by wires (hee hee...)... also U r not going to
program it very often, it will be one time JOB...
OPTO-ISOLATOR is a great idea if u r willing to interface the DC
circuit with some other device... but if U want to make the whole
system stand alone, u can surely avoid them to make whole setup
cheaper...
---
Raj
--- In Electronics_101@y..., Jim Purcell <jpurcell@w...> wrote:
yahoo,
I am working on a circut which uses a EEPROM made by Parallax to
animate a string of christmas type lights. I intend to have four
separate 120vac outlets that are switched on and off (dimming
would
be nice) by the EEPROM. Obviously, the outputs EEPROM can not
handle
much current at all.
Memories of any kind are not designed to drive anything but other
circuits.
In addition digital devices won't like AC. What you will need is a
triac for
each AC device. In addition I would use opto isolators to couple the
controlling signals to the triacs and probably buffers to control
the opto
isolators. An opto isolator is a device that uses some kind of
light source,
usually LED's to turn on and off another device, like a transistor
or a
triac, etc. A buffer is a device that draws very little current
from the
input device but can deliver larger current to the output device.
Jim
I thought of using the EEPROM to control a small
relay and hook the contacts of the small relay to a coil of a
larger
relay to turn the light on and off, but I would like to use some
kind
of solid state circut to control the 120vac (that way I could
implement dimming). Any thoughts on how I can control the 120vac
with
a small current. Sorry I don't know the exact peak current the
outputs on the EEPROM can handle.
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