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little phase control to 135º

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Thread Starter

silvajq

Joined Apr 14, 2010
7
Hello everybody,
I have proble, i wan to build a phase control to control my output from 0º to 180º. i just search for everywere, and i jus tmade one to control for example a lamp. but now i have a new project, my supplie AC voltage is about 5VAC, and i want to control the phase with this value, for a maximum out put of 1amp. i hust try with TCA 185 and so on and i'm not able to put it working, can someone give a litle help?
I'm new member, i just take a look to forum and it is fantastic!
Regards,
Silva
 
t06afre

t06afre

Joined May 11, 2009
5,934
Have you tried to use the all-pass filter. You will find info about on wiki. I have never used it my self so I do not know how useful it is as a design element
Edit: This is perhaps not that the OP had in mind. I think I misunderstood the request. Sorry for that
 
Last edited:
DickCappels

DickCappels

Joined Aug 21, 2008
10,170
A couple of ideas spring to mind. The simplest from a conceptual point of view is to use a monostable multivibrator that triggers at the zero crossing and triggers you triac of SCR a time later. Simpler still, but more direct is to use a two pol RC circuit to delay the rise in the trigger voltage.

If you post the circuit you are now working with, i am sure you can get more speicific answers.
 
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rjenkins

Joined Nov 6, 2005
1,013
Have a look at a Programmable Unijuntion Transistor like 2N6027.

With a few components you can make good phase control dimmer.

Have a look at figure three in the datasheet.
http://www.onsemi.com/pub_link/Collateral/2N6027-D.PDF

Change the 510K fixed resistor to a 1K plus a 470K pot and make Cc about 0.1uF?? Cant remember the ideal value.

Feed the circuit from full-wave rectified but *unsmoothed* 12V.

If you use a 12V center tapped transformer you can use the center tap for a lower voltage supply to your lamp? and the other side of the lamp to the anode of a small thyristor.

Connect the thyristor cathode to timing circuit negative and the gate to the top of the 20 Ohm resistor via a 10 ohm.
 
S

Thread Starter

silvajq

Joined Apr 14, 2010
7
DickCappels said:
A couple of ideas spring to mind. The simplest from a conceptual point of view is to use a monostable multivibrator that triggers at the zero crossing and triggers you triac of SCR a time later. Simpler still, but more direct is to use a two pol RC circuit to delay the rise in the trigger voltage.

If you post the circuit you are now working with, i am sure you can get more speicific answers.
Click to expand...
i try with two different circuits, that you can see in the atachments, but they are all for a 230vac inputs, and i want to do it for at maximum 12vac. i just simulate the 2 circuits on the multsim with 12vac and with all components with exact value and it works fine :) but when i assembly it on pcb board, the circuit didn't work! on the first circuit i switch the diac to one diod 1n4007

Silva
 

Attachments

Last edited:
S

Thread Starter

silvajq

Joined Apr 14, 2010
7
rjenkins said:
Have a look at a Programmable Unijuntion Transistor like 2N6027.

With a few components you can make good phase control dimmer.

Have a look at figure three in the datasheet.
http://www.onsemi.com/pub_link/Collateral/2N6027-D.PDF

Change the 510K fixed resistor to a 1K plus a 470K pot and make Cc about 0.1uF?? Cant remember the ideal value.

Feed the circuit from full-wave rectified but *unsmoothed* 12V.

If you use a 12V center tapped transformer you can use the center tap for a lower voltage supply to your lamp? and the other side of the lamp to the anode of a small thyristor.

Connect the thyristor cathode to timing circuit negative and the gate to the top of the 20 Ohm resistor via a 10 ohm.
Click to expand...
Sorry Robert,

I don't understand what you mean on your last paragraph "Connect the thyristor cathode to timing circuit negative and the gate to the top of the 20 Ohm resistor via a 10 ohm"

Silva
 
S

Thread Starter

silvajq

Joined Apr 14, 2010
7
eblc1388 said:
@Silva,

Try the following component changes to see if the the IC works. I have not tested it so good luck for the trial.

Click to expand...
Hi,

Didn't work, in my opinnion all the components are prepared for a imput of 230vac, and this way will no work :,(
 
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rjenkins

Joined Nov 6, 2005
1,013
Figure three in that data sheet has a circuit with the output across a 20 Ohm resistor.

That would be where to to connect to a thyristor, with the gate via a 10 Ohm resistor to limit the current.
 
S

Thread Starter

silvajq

Joined Apr 14, 2010
7
eblc1388 said:
Please measure voltage across 470uF 16V capacitor and post back.
Click to expand...
Hello, sorry my delay, but i was on holidays, so finally the circuit is running (with the TCA), the problem was in my test board!! she had some contacts broken!

I want to thank you and to the other users that help me!

Silva
 
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