Now I'm trying to make a digital dimmer I found in a known magazine. The thing is that the circuit in the magazine is for 230vac/50hz. My house mains are 110vac/60hz. What changes will I need to rework in the circuit? What calculations will be necessary and how can I make them. Will this affect the firmware? See tha attached schematic. Thanks in advance for your help, electronics friends.
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Depending on the software in the PIC and the power supply reserves you might not have to change anything at all.
You may however have to rewrite the software to suit the 8.33ms timing instead of 10ms.
Hardware changes: you might possibly need to increase the size of the 220nF cap.
A capacitor that will provide the same current: 220/110*230/1.2=383nF (use 390nF or less).
You may however have to rewrite the software to suit the 8.33ms timing instead of 10ms.
Hardware changes: you might possibly need to increase the size of the 220nF cap.
A capacitor that will provide the same current: 220/110*230/1.2=383nF (use 390nF or less).
That's from an article in Silicon Chip magazine.
You can email a letter to the editor and any which are published appear on their web site (the main articles are behind a paywall though)
If the code is available, it too is *IN FRONT* of the paywall - i.e. you don't have to pay.
If I can find more information for you I'll edit this post.
Edit:
OK, if this is the device, then this is the PIC code.
They include source. You will need to make changes for 60Hz, I would suggest changing the values for
and would draw your attention to the following code:
Even if you make changes here, it may still be worthwhile contacting them as there may be other modifications they might suggest (particularly in the power supply area)
You can email a letter to the editor and any which are published appear on their web site (the main articles are behind a paywall though)
If the code is available, it too is *IN FRONT* of the paywall - i.e. you don't have to pay.
If I can find more information for you I'll edit this post.
Edit:
OK, if this is the device, then this is the PIC code.
They include source. You will need to make changes for 60Hz, I would suggest changing the values for
Code:
PULSE_O equ H'23' ; operational pulse value
DIVID_O equ H'24' ; operational divide valueand would draw your attention to the following code:
Code:
; POSITION counter timer 250 counts = 10ms (count 20 is 14 degrees for max brightness and count
; 220 is 158 degrees or min brightness start point.
COUNTER
incf POSITION,f ; position in half wave starting from zero crossing point
; adjust interrupt rate with counter
movf DIVIDE,w ; divide value
movwf DIVID_O ; operating divide valueEven if you make changes here, it may still be worthwhile contacting them as there may be other modifications they might suggest (particularly in the power supply area)
Last edited:
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220nF*(230V/110V)-20%
The voltage has more than halved (110/230=0.4478) so the capacitance has to more than double (230/110=2.09).
But then the frequency has increased by 20% (60/50=1.2) so the capacitance has to decrease by 20%.
You may very well get away with a 330nF cap. if the original design has some built-in reserve.
Capacitor Current = Voltage / (1 / (2 * pi * frequency * capacitance)) = 16mA (of which only half is available due to half-wave rectifying).
The voltage has more than halved (110/230=0.4478) so the capacitance has to more than double (230/110=2.09).
But then the frequency has increased by 20% (60/50=1.2) so the capacitance has to decrease by 20%.
You may very well get away with a 330nF cap. if the original design has some built-in reserve.
Capacitor Current = Voltage / (1 / (2 * pi * frequency * capacitance)) = 16mA (of which only half is available due to half-wave rectifying).
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