Direction of current

[legend killer]

Hi guys,
even though i m in 2nd year of my college,i m confused by very basic concept of electronics.suppose i have an alternating voltage source and i connect a resistance across it.if current flows in one direction for +ve half cycle,then will it flow in opposite direction for -ve half cycle.
My book says that it does flow in opp.direction but my teacher says other way round.
I m completely baffled.hope u can help

 

[crutschow]

You have it right.

What does the teacher mean by "other way round."?

 

[legend killer]

He says that that it continuous to flow to flow in only one direction,even though the voltage reverses its polarity

 

[ericgibbs]

Hi guys,
even though i m in 2nd year of my college,i m confused by very basic concept of electronics.suppose i have an alternating voltage source and i connect a resistance across it.if current flows in one direction for +ve half cycle,then will it flow in opposite direction for -ve half cycle.
My book says that it does flow in opp.direction but my teacher says other way round.
I m completely baffled.hope u can help

hi,
Are you confusing the actual electron current flow direction with the conventional current flow direction.??

 

[legend killer]

Hey eric,i want to understand the behaviour of current direction,whether it is conventional flow or electron flow.
I think about the concept of alternating voltage as the voltage which reverses its polarity.m i right about it??

 

[crutschow]

He says that that it continuous to flow to flow in only one direction,even though the voltage reverses its polarity

Your teacher is wrong. In a resistive circuit, the current flow direction follows the voltage direction. For conventional current flow it's plus to minus, for electron flow it's minus to plus.

He is obviously not a very knowledgeable teacher, so be skeptical of anything he says.

 

[ericgibbs]

hi,

As Carl says, 'ac' is defined as 'alternating current' ie: the current alternates in direction as the phase changes polarity.

Why dont you ask your 'teacher' to explain his version of 'ac'..

 

[legend killer]

I nee some more help about alternating voltage.while i was experimenting with transistor,i gave the input signal to it from function generator.The probes had two wires -one on the peripheri and other in the centre. i connected the wires randomly-one to the base and other to the ground..but i did not got the output.then i connected the wire the reverse way i.e the wire to the ground now connected to base and vice versa there was the output.how does it matter if the input is sine wave...plz help

 

[audioguru]

Maybe the teacher thinks that the electrons flow in one direction when the polarity is one way then the conventional current flows in the same direction when the voltage is the other way round.

 

[BrownOut]

^ -- You're evil

 

[smanches]

I nee some more help about alternating voltage.while i was experimenting with transistor,i gave the input signal to it from function generator.The probes had two wires -one on the peripheri and other in the centre. i connected the wires randomly-one to the base and other to the ground..but i did not got the output.then i connected the wire the reverse way i.e the wire to the ground now connected to base and vice versa there was the output.how does it matter if the input is sine wave...plz help

AC still has a live and neutral wire. Kind of like the positive and ground wires in DC. If you hook them up backwards, then you would be putting the signal from emitter to base, instead of base to emitter of the transistor.

 

[audioguru]

A transistor needs to have its base biased preperly to pass or amplify a sine-wave.

 

[Sceadwian]

Conventional current flows from positive to negative voltages, however the actual electrons flow from the negative to the positive. Electron flow is almost never used unless you're talking physics or chemistry. I think you may have simply misunderstood what your teacher said.