MC3334 question

[Michael Fawke]

At 01:42 AM 6/3/1996 -0500, Sandy wrote:

>At 09:55 AM 3/6/96 +1000, you wrote:
>>Pardon my ignorance, but I am a computer programmer and my knowlege of
>>analogue is _very_ limited....
>>
>>On the MC3334, when used to drive an MJ10012 (?) with current sense, the
>>circuit diagram I have shows a .027 Ohm resistor bewteen ground and the 
>>MJ10012, with the sense taken from the MJ10012 side. In Tim Drury's article
>>on Distributorless ignition, he gives a circuit for the ignitor which does
>>not have this resistor. I am assuming the resistance is necessary for the
>>current sense to work, - so what can be used to create this resistance, or
>>can it really be discarded (as per Tim Drury's design)?
>>
>I don't have the circuit handy (i'm on the road), but I thought that it had
>the sense resistor. The value on the moto data sheet is .075Ohms I think.
>Their is also a variable resistor from that to form a simple divider network
>that is used to adjust the current that the limiting starts at. The thing
>that I remeber from Tim's stuff is that it was the exact same circuit as the
>moto data sheet. 
>

Hmmm - nope, the .075 ohm resistor is missing from Tim's circuit (the Net
version anyway). What resistor do you use here? Obviously this is not 
something that you buy off the shelf.... Maybe several pieces of resistance
wire to carry the current?
 
Michael Fawke
fawkacs at ozemail.com.au