Tricky BJT Circuit

[newbe_always]

Can you please solve the problem attached.It is very confusing to me

 

[Nigel Goodwin]

If may help to redraw with conventional higher above lower or negative supplies.

Nope, that makes it FAR worse

And in any case, that isn't the 'convention' - it's equally 'correct' either way, mostly based on the era in question - this is a (very poorly written) very old question, from back when almost all transistors were PNP, and so the chassis was positive.

As I've said in these forums many times, it makes far more sense to ignore negative and positive, and just think of high or low - so for a positive earth circuit (like this one) negative 8 volts is higher than ground.

But in any case, the question is very poorly written, makes no real sense, and whoever wrote it wants taking out and flogging - except they are probably long dead, and (as was common among exam question setters) probably had no electronic knowledge anyway (often they were supposedly written by English teachers).

 

[Tony Stewart]

Nope, that makes it FAR worse

And in any case, that isn't the 'convention' - it's equally 'correct' either way, mostly based on the era in question - this is a (very poorly written) very old question, from back when almost all transistors were PNP, and so the chassis was positive.

As I've said in these forums many times, it makes far more sense to ignore negative and positive, and just think of high or low - so for a positive earth circuit (like this one) negative 8 volts is higher than ground.

But in any case, the question is very poorly written, makes no real sense, and whoever wrote it wants taking out and flogging - except they are probably long dead, and (as was common among exam question setters) probably had no electronic knowledge anyway (often they were supposedly written by English teachers).

Ha. I remember flying in the early 80's around Silicon Valley when my co-passenger was a psychology major acting as a Test Engineer for National Semi. asking me what ATE with flying probes he should use for their new microprocessor.

Yah I used to own a '63 MGB with positive ground batteries. (2x6v) and I agree with the |absolute value| thinking. Otherwise Murphy's Law will offer the wrong polarity somehow.