Circuits questions

[Jay2903]

I figured someone here might know the answer to this and have an explanation cos im a bit confused.
(This is an automotive test question)

Using the diagram what are the voltage readings when the wiper switch is moved to the wiper speed two position. The supply voltage is 12v.

[Jay2903]

A) pin 4 - 0v , pin 5 - 0v , pin 3 - 12v
B) pin 4 - 12v, pin 5 - 0v, pin 3 - 0V
C) pin 4 - 12v, pin 5 - 12v, pin 3 - 12V
D) pin 4 - 12v , pin 5 - 0V, pin 3 - 12V

[Nobby the Bastard]

In position 2 only pin 5 will get voltage and will be 12 v.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Jay2903]

[Pete.]

None of the above.

Pin 3 only gets power when the washers are activated which isn't mentioned so going by that the only possible answer is B as it's the only one with 0v on pin 3.

Wiper speed 2 is position 4 which puts 12v to both pin4 and pin5 so going by that the only possible answer is C.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[MCN]

[WD Forte]

It's a poorly written question IMO

If we assume the low points ( switches) all share a common ground as looks likely
and assume the upper pins ( 3,25,4,5) are all at 12v for arguments sake
then in position 2:
pin 3 will stay high (12V)
pin 4 will stay high (12V)
pin 5 will be pulled low (0V)
so answer D
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bikers smell of wee

[Pete.]

[Jay2903]

I’ve got the whole diagram now.

[Jay2903]

I thought
Pin 5 - 12v
Pin 4 12V
Pin 3 - 0V
But that’s not an option.

[Jay2903]

Oh my bad A
Pin 5 - 0v
Pin 4 - 0V
Pin 3 - 12v

[WD Forte]

Its feckin D!
pin 5 is obviously pulled low in position 2 so wil be low/0V
pin 4 remains open circuit so high/12v
pin 3 remains open circuit so high/12v

Its still a shit question as the pins are connected not to a 12v supply
but to the emitters of transistors
Unless these transistors are turned on by a voltage at their bases, you could easily argue the voltages at the emitters(pins)are all floating/indeterminate subject to leakage current.

the 15's look like current limiting resistors between each collector
and the 12v power rail
the arrows will go high when the tranny is off and low when on and the emitters connected to ground

The poorly written question forces us to assume they're all turned on so in that case D
____________________
bikers smell of wee

[Pete.]

[WD Forte]

What?
bollox
As I have comstantly maimtained, its A, hi-lo-lo then


____________________
bikers smell of wee

[jeffyjeff]

Let's write a test question that looks simple at first blush. After reading it for the sixth time you realize that your knee jerk conclusion is way off the mark. Then let's omit the correct answer from the test, just to screw wit the little fuckers. That's the way to do it.
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History shows again and again how nature points out the folly of men - BOC