i found this in my dod pedal,does it mean zero ohm ? if so ,why not just install a jumper ?  :roll:

You're right it's probably 0 ohms. It looks neater than a jumper, and there was another reason that I can't remember right now... I'm sure someone will chime in... :roll:

I think it's a jumper, but I don't know why to use them instead of a common jumper. Maybe to give a better look for the board.

My guess would be so automated assembly machines that grab resistors & stick them in boards don't have to grab a piece of wire instead. I doubt it's for looks, but rather practicality.

RDV

Quote from: RDVMy guess would be so automated assembly machines that grab resistors & stick them in boards don't have to grab a piece of wire instead. I doubt it's for looks, but rather practicality

I like the sound of that!  You don't happen to smoke a pipe and play the violin do you?

Zero-ohms "resistors" are often used for automated assembly, especially for surface mount. The advantage is that you don't have to "teach" the machine to mount another sort of package. So, yes,  it boils down to: just a jumper.
Kindest regards: Bernt.

wow,thanks guys........ i do see "j1,j2" instead of "r1,r2" next to those 0 ohm resistors,now i got it, thank you so much  

They're also handy for automated assembly if you decide you didn't need a resistor in that location after all. Because of this they may still be labeled R14, R15, etc.

Take care,
-Peter

Quote from: gez

Quote from: RDVMy guess would be so automated assembly machines that grab resistors & stick them in boards don't have to grab a piece of wire instead. I doubt it's for looks, but rather practicality

I like the sound of that!  You don't happen to smoke a pipe and play the violin do you?

Elementary, my dear Gezson! :wink:

RDV Holmes

ScheMATHic...I sometimes see if a component is wired so current flow is only given one path of least resistance, then measure that in cct.
 Of course a good long look at the schematic is necessary, and sometimes a little math to use this method, but I find things in Cct. this way sometimes...in the case of a suspected wire...chances are that DMM beep mode will determine if there is a connection across that part [ie wire] and finding that there's no other possible way for that to occur except through that part would probably not be very hard. I think it could be verified as acting like a wire, using this method.
 I've found all kinds of funny resistances/non resistances in Cct., but...if theres a way for the current to flow around the in cct component with less resistance the method is useless. Sometimes the math [adding R values or dividing them] helps make sense of in cct readings...but I think I'm alone in typing about it, and don't know that I'd recommend it as a usual debugging method...with all the ifs, buts, and notwithstandings involved in it's use. It has as a last resort method saved what seemed otherwise doomed boards. Time consuming, imprecise and tedious.