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120VAC Lamp switched by cmos circuitry?

Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?
 
A

Anthony Fremont

Jan 1, 1970
0
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?

Relays? How much current are you talking about, are these standard bulbs
(60-100W)? If you need it to be fairly small, then triacs may be the way to
go.
 
D

D from BC

Jan 1, 1970
0
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?

What's wrong with a relay?
D from BC
 
D

DJ Delorie

Jan 1, 1970
0
cmos -> transistor -> optoisolator (triac driver, zero crossing) ->
triac or alternistor

That's what I use. The key is layout - keep low voltage copper away
from high voltage copper, use larger trace/space for high voltage,
plan for insulating the high voltage section to protect the user.

Use an alternistor if you expect inductive loads.
 
M

me

Jan 1, 1970
0
[email protected] wrote in @w1g2000hsg.googlegroups.com:
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?

A relay or a solid state relay. I think Radio Shack (cringe) might still
sell one that can switch up to 3 amps at 125 VAC...
 
D

Donald

Jan 1, 1970
0
DJ said:
cmos -> transistor -> optoisolator (triac driver, zero crossing) ->
triac or alternistor

That's what I use. The key is layout - keep low voltage copper away
from high voltage copper, use larger trace/space for high voltage,
plan for insulating the high voltage section to protect the user.

Use an alternistor if you expect inductive loads.

Solid State Relay.

http://dkc3.digikey.com/PDF/T071/P1772.pdf
 
M

MooseFET

Jan 1, 1970
0
cmos -> transistor -> optoisolator (triac driver, zero crossing) ->
triac or alternistor

That's what I use. The key is layout - keep low voltage copper away
from high voltage copper, use larger trace/space for high voltage,
plan for insulating the high voltage section to protect the user.

Don't have a "ground plane" going between the two areas.

Put the low voltage signals on a connector on one end of the PCB.
Put the high voltage signals on a connector on the far end of the PCB.

Make sure to pick connectors that can't be partially or fully mated
wrongly.

In other words assume an idiot is going to work on it. The idiot may
even be you one sleepy morning or late night.
 
L

LVMarc

Jan 1, 1970
0
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?
Go Purdue!

You need two things:

A relay made for 120 vac and about a 1KW CONTACTOR rating. P$B T92
seies for this.

An interface to go from the PIc I/o pin and to drive the Coil part of
the T92 contatcor relay. We use this in the backend of a wireless prime
power actuator switch. Link here..

http://www.pacificenergyserviceconsulting.com/07ccm4t23.pdf

Contact me for a breadbaord

Marc
 
J

Jan Panteltje

Jan 1, 1970
0
Go Purdue!

You need two things:

A relay made for 120 vac and about a 1KW CONTACTOR rating. P$B T92
seies for this.

An interface to go from the PIc I/o pin and to drive the Coil part of
the T92 contatcor relay. We use this in the backend of a wireless prime
power actuator switch. Link here..

http://www.pacificenergyserviceconsulting.com/07ccm4t23.pdf

Contact me for a breadbaord

Marc
eh,
From MOC3010 triac output optocoupler application note:
http://www.fairchildsemi.com/pf/MO/MOC3010-M.html
http://www.fairchildsemi.com/ds/MO/MOC3010-M.pdf
Look at page 5 of the PDF for diagram.
Been in use here for almost 10 years... (at 230V even :)).
Switching > 10A with it with an additional thyristor.
 
J

jasen

Jan 1, 1970
0
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

mc3020 and a triac, - google for 3020+datasheet

Bye.
Jasen
 
E

Eugene Rice

Jan 1, 1970
0
Hey guys. I'm a CompE student so my electrical design knowledge
regretfully doesn't extend far into SAFELY controlling high voltages.
I have five 120V AC lightbulbs on a lamp and I need to control them
individually with a computer. I've constructed the lamp, written the
software, and built the computer interface, but can anyone recommend a
way to safely control 120V with a 5V DC control line?

Or can you recommend a fairly inexpensive switch I can buy?
Crydom solid state relays.

We used them in the 70s and I'll be damned they still make them and
Digikey has them in stock.

They start at US$23 -- not sure if that satisfies your cost criterion.

Geno
 
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