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[windmill john]

“ In short its electronics to fool your engine into getting more fuel in and it's done by getting bits to work by fiddling the numbers to fit”

Ahh, fully understand that

I’m happy with my ‘mechanicing‘ skills, my carb fiddling... I’ll just stay away from the wiry stuff.

[Andy C]

John

"In terms of current slightly more current will flow through the 47k resistor than the 10k resistor simply because it is a lower resistance. Just go through slightly more current when 47k is higher resistance than 10k? Surely less current would flow? Ohm’s law."

My error - of course more current goes through the lower resistance - which is 10k Doh !

“ In short its electronics to fool your engine into getting more fuel in and it's done by getting bits to work by fiddling the numbers to fit”

Yep that is it in a nutshell.

[windmill john]

Thanks both and thanks again Andy for clearing that up.

Wheaters, I’ve always read about the water analogy, but there a point Where that’s not enough and I’m trying to break into that world.

If I switch off my too questioning head, it simply looks like the only purpose of the other resistor, is to allow a higher current through the thermistor.

There must be a range issue and I will ignore my own question of why not use a lower resistance thermistor. Definitely slightly a black art.

[Andy C]

John re "why not use a lower resistance thermistor"

It is because 8.2k is not a standard thermistor resistance value - try googling "table of standard thermistor values" you will see what I mean.

All resistors, thermistors and many other electronic components such as capacitors come in "standard" values - again google and you will see what I mean.

Re the water analogy, its a pretty good way of looking at things except a water leak is earier to see

[Beezabryan]

My brain hurts!

[Wheaters]

If I switch off my too questioning head, it simply looks like the only purpose of the other resistor, is to allow a higher current through the thermistor.

Not so, it provides a “bypass” so it allows the correct amount of current to pass through the thermistor. The thermistor is likely to be an “off the shelf” component, also used for other things elsewhere. Fitting the resistor allows it to be matched to the required purpose.

[windmill john]

The thermistor is likely to be an “off the shelf” component, also used for other things elsewhere. Fitting the resistor allows it to be matched to the required purpose.

That makes sense.

I’ve just been talking to my wife about this (okay, we were sat eating and she’d had wine, so couldn’t escape) and how often and for how long the water analogy has been used; it only goes so far.
I think seeing part of an electric circuit in isolation doesn’t help, you need to see the bigger picture (I struggle with this bit).

I do understand why you can’t, for example, just have a circuit: battery positive-wire-switch-wire-load-wire-battery negative. It’d makes electrics easier for me Yes I know we do in a torch before someone comments

[Wheaters]

Look up the term “electrical shunt”. Lots of information online, which might help your understanding.

[windmill john]

Oooooh.... the mists slowly clear.... thanks Wheaters.

I’ve just read a little bit on two or three sites; needs more reading. But there are a number of reasons for the shunt. But I can see they might be there just as a protection for the load/device/thermistor. Might be a current reason, a control reason.

I’m going to do some swotting.

[RocketRR]

You need to get out and do some riding lol