I modify a FC4 Board to work on 18 VOLTS AC instead of 120 Volts AC UPDATED
sam_sam_sam
Posts: 2,286
More to come...... Please wait...... This forum is dropping what in being typed and loose the hole post it must be timing out then telling me that my password is not valid·and when typing the password in again·it still says invalid password
when hitting the SUBIT button the only way·for me to get back on the forum is to close Internet explorer and open
Internet explorer· then every thing is OK again
This has·happen before and some time it·get on my nerves and just·want to throw the computer at the wall
Enough of this...........>>>>>>.........>>>>>>>>>........................
Disclaimer
I know that to·modify the FC4 board will void my warranty I know this
But if i do not at least give this a try i will ask would this work
I have played with the demo code for the FC4 Board and i wrote a demo for each function very nice
Board and easy to write the code for it
Hi Every One
I am at it again with some project
This what i want to
The FC4 Board has two resisters at the input of the optic sensor· the value are 15 k ohm for both of them
the voltage at the input pins is 1.2 Volts AC
The triac has a resistor that a value of 180 ohms between two of it pins will i··need to adj this value if so to what value
What i need to know is·what this·value need to be for the resistors at the input of the optic sensor
I·want ·to have this work on 35 Volts AC instead of 120 VOLTS AC
·the optic sensors input see 1.2 Volts AC At 35 Volts AC
Now I am not very good at using the ohm law pie chart
Please for give me for this short coming
Dose any one any reason that this will not work
Please let me if you see a reason why this will not work
Here what i want do with this set up
I want control the light level of the Low Voltage Light that i want to Install in my yard
I want be able to dim the lights at will and who know what else at this point
I have not got that far yet as far as who know what...
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··Thanks for any·
·that you may have and all of your time finding them
·
·
·
·
Sam
Post Edited (sam_sam_sam) : 9/24/2007 4:24:20 PM GMT
when hitting the SUBIT button the only way·for me to get back on the forum is to close Internet explorer and open
Internet explorer· then every thing is OK again
This has·happen before and some time it·get on my nerves and just·want to throw the computer at the wall
Enough of this...........>>>>>>.........>>>>>>>>>........................
Disclaimer
I know that to·modify the FC4 board will void my warranty I know this
But if i do not at least give this a try i will ask would this work
I have played with the demo code for the FC4 Board and i wrote a demo for each function very nice
Board and easy to write the code for it
Hi Every One
I am at it again with some project
This what i want to
The FC4 Board has two resisters at the input of the optic sensor· the value are 15 k ohm for both of them
the voltage at the input pins is 1.2 Volts AC
The triac has a resistor that a value of 180 ohms between two of it pins will i··need to adj this value if so to what value
What i need to know is·what this·value need to be for the resistors at the input of the optic sensor
I·want ·to have this work on 35 Volts AC instead of 120 VOLTS AC
·the optic sensors input see 1.2 Volts AC At 35 Volts AC
Now I am not very good at using the ohm law pie chart
Please for give me for this short coming
Dose any one any reason that this will not work
Please let me if you see a reason why this will not work
Here what i want do with this set up
I want control the light level of the Low Voltage Light that i want to Install in my yard
I want be able to dim the lights at will and who know what else at this point
I have not got that far yet as far as who know what...
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any·
·that you may have and all of your time finding them·
·
·
·
Sam
Post Edited (sam_sam_sam) : 9/24/2007 4:24:20 PM GMT
Comments
Okay, the input opto-coupler that provides the zero-cross timing to the SX is the H11AA1; it has a forward voltage of 1.2 volts with a max current of 10 mA. If your new voltage is in fact 35 VAC (are you sure it's not 24?), then the peak voltage will be approximately +/- 49.5 volts. So...
49.5 - 1.2 = 48.3 (volts across the series resistors)
48.3v / 0.01 A = 4829 ohms
4829 / 2 (resistors) = 2415 (find the next highest 1/2 resistor value), probably 2.7K (this should allow about 8.9 mA (plenty of current).
As for the 180 resistors on the output of the MOC3023, there is less design guidance from Motorola et al on that. But... "standard" circuits show 180 for 120 VAC, and 360 for 240 VAC, so it *may* be safe to assume you can drop that to approximately 62 (fairly standard value for 1/4 w) ohms for 35 VAC.
I make NO GUARANTEES that either of these modifications will work; you are on your own.
Note: If you change any component on the board you do so at your own risk. Neither me (Jon Williams), EFX-TEK (manufacturer of the FC-4), or Parallax (as they're hosting this discussion) are responsible for any consequences that result from your modification. AC circuits can be dangerous -- you've been warned.
I make NO GUARANTEES that either of these modifications will work; you are on your own.
Note: If you change any component on the board you do so at your own risk. Neither me (Jon Williams), EFX-TEK (manufacturer of the FC-4), or Parallax (as they're hosting this discussion) are responsible for any consequences that result from your modification. AC circuits can be dangerous -- you've been warned.
I fully understand these term and understand that· AC circuits can be dangerous
Have worked with AC circuits for many years and understand the risk
But this is why i was asking the thing that i was asking
I did not want to try· just putting any value resister in it place
Jon Thank You for warning about the dangers of AC circuits and all the rest
Also· thank you for your help in this matter
I had use a ohms law calculator on the internet· but i used the value of
4 millamps instead of 10 millamp i came up with 8750
ohms @ 35 volts with no load on the tranformer
The· voltage is in fact·24 VAC·the peak voltage·is approximately +/-·35.8
This helped alot
49.5 - 1.2 = 48.3 (volts across the series resistors)
48.3v / 0.01 A = 4829 ohms
4829 / 2 (resistors) = 2415 (find the next highest 1/2 resistor value), probably 2.7K (this should allow about 8.9 mA (plenty of current).
·
Where i got the 4 millamps was I inputed the·voltage·at 120 volts the resister value at 30000· ohms .... And used the calculator on the internet·
Here is the link that i used
http://www.cortezkat.com/cortez_fishing_center/ohm.htm
I will let you· how this work or if it dose not work
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··Thanks for any·
·
·
·
·
Sam
Post Edited (sam_sam_sam) : 9/20/2007 9:52:14 PM GMT
Have an Up Date about if the FC4 board will work on·18 volts
Yes it will even work down to 12 volts
·All you have to do is change· the resistors at the input of the optic sensor·to a value of·4400··Ohms·This is for 18 Volts AC·
The the volts at the input of the optic sensor··is 1.2 volts Make sure that it is
1.2 volts because the·leds on the board will·not work right if it is below 1.2 volts
You do not need to change· the value of·this resistor at the trica
I had CHANGED the value to 80 ohms at the triac
The triac and the different was only .25 volts at full ON
We are so happy that this works very well even on 12 Volts ......
·············································· · Jon Thank You For All of Your Help And Time
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··Thanks for any·
·
·
·
·
Sam
Post Edited (sam_sam_sam) : 9/24/2007 4:39:59 PM GMT