electronics101@groups.io

Re: Triac instead of relay ?

Curtis Sakima

Got it.

I'll try modifying future mail so you can see it.

Curtis

Dazzle Mom this coming Mother's Day season with flowers!

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----- Original Message -----
From: Steve <alienrelics@...>

I'm reading online so I can't see either picture, but I think I know what
they look like.

Alien Steve

Re: Triac instead of relay ?

Curtis Sakima

#9701

I think we could be getting into a semantic war with this thing.  So ....
instead of my talking anymore ... please ... everyone open up the *.bmp
attachment of this email.  THIS .... is what I saw on the scope output of
the triac dimmer.  The arrows indicate what moves as I dim the lamps up and
down.   The overall wave doesn't shift ... but that vertical line (indicated
by the arrows) ... shifts left and right.

As the area under the curve varies ... so does the intensity of the lamps.
I thought a picture might settle this.

Curtis

Dazzle Mom this coming Mother's Day season with flowers!

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----- Original Message -----
From: Steve <alienrelics@...>

As you say, the turn on point shifted... but the turn off point does-not-
shift.

Re: SMD's(Thanks All)

Curtis Sakima

#9687

Much agreed.  Those were the days of individual still able to get a lot of
parts (no need to be a shop).    Also when Auto emissions were not such a
big deal (hotrod ....  DIY Weber Carbs ... headers ... etc.).   Yes ...
those were the days of much DIY.

Me too .... 911 ... lost good electronics job.

Curtis


Dazzle Mom this coming Mother's Day season with flowers!

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----- Original Message -----
From: Kenneth Smith <kensmith52@...>


Well I graduated in 1966. Took Electronics last 2 years of HS.  Lost 2 good
jobs during the mid 80's when all the companies were merging and again 2
jobs after 911 due to business going down. Decided to start my own.

I was very lucky as I was growing up that people would spend time to show me
the things about electronics. I try to pass it on to others that need it and
willing to learn. That is why this forum is good.  There are a lot of
knowledgeable people on here so the beginers can learn a lot.

Re: Triac instead of relay ?

Curtis Sakima

#9686

I used to work fixing stage-n-lighting light dimmers.   We used
oscilloscopes triggered by the incoming line AC.   The output sine-wave
never shifted left and right as dimming was varied.   Just the sharp
vertical line from "zero" where the triac triggered ... went "left and
right".

Curtis

Dazzle Mom this coming Mother's Day season with flowers!

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----- Original Message -----
From: Steve <alienrelics@...>

Since the turn on point is delayed: The voltage and current in a resistive
load are in phase. However, if you look at the voltage coming into the whole
circuit, the current phase is delayed because of the delay between zero
voltage crossing and when the triac turns on and causes the start of current
flow.

Other ideas Was: 555 Filter

Curtis Sakima

#10347

Anyone thought of using a standard audio power amp with say, +/- 50 supply
rails??  Then a sine wave oscillator could simply be hooked up to drive it.

Another idea would be to use a class-D audio amplifier .... whose output
would be a +50 volt to -50 volt swinging  250 Khz square wave ..... Pulse
Width Modulated at a rate of 16 Hz (sinusodal).   Low Pass filter this ....
voila ..............

Curtis

Dazzle Mom this coming Mother's Day season with flowers!

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----- Original Message -----
From: genteelu4ia <vortex_9x@...>

ST, I was thinking ( that's where I get in trouble) I needed a sign wave to
properly go through the setpup transformer to increase the voltage to 30v
AC-- I do need AC on the output.

I was thinking that a square wave would only produce a short pulse after
going through the transformer.

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