allenf
Member level 3
Ok guys heres one for you to solve.
BIG argument going on between me and the guy i`mdoing the schematics and layout for.
regulators are LM317`s
He has four PICS (2x8pin and 2x 18pin) the 8 pins drive the 1x 18 pin the other 18 pin is driven direct from regulator.
the other regulator is powering 8 pwm leds..
(so far??)
He reckons that on the TWO lm317s thathe is insistant that i use that i can get away with 0805 size chip resistors for r1 and r2 (the limit resistors)
I reckon that it would need at LEAST 1206 size to handlethe wattage,
he says I`m stupid and cant add up but the way i see it its simple math that is an 805 is 1/12 watt ( or 0.8) so 5 volts X (8x20mw) EXCEEDS the maximum of the 805..
Can somone please referee this one and say who is right who is wrong before we strangle each other.
Normally i would build it and proove a poin but 4 layers and a board house is gonna be pricey to proove a point IMO
Thanks in advance
Allen
BIG argument going on between me and the guy i`mdoing the schematics and layout for.
regulators are LM317`s
He has four PICS (2x8pin and 2x 18pin) the 8 pins drive the 1x 18 pin the other 18 pin is driven direct from regulator.
the other regulator is powering 8 pwm leds..
(so far??)
He reckons that on the TWO lm317s thathe is insistant that i use that i can get away with 0805 size chip resistors for r1 and r2 (the limit resistors)
I reckon that it would need at LEAST 1206 size to handlethe wattage,
he says I`m stupid and cant add up but the way i see it its simple math that is an 805 is 1/12 watt ( or 0.8) so 5 volts X (8x20mw) EXCEEDS the maximum of the 805..
Can somone please referee this one and say who is right who is wrong before we strangle each other.
Normally i would build it and proove a poin but 4 layers and a board house is gonna be pricey to proove a point IMO
Thanks in advance
Allen