About John Penton Expertise I am happy to answer questions on semiconductor devices - in particular high-voltage devices.
Also any electronics or physics homework questions.
I`m not a semiconductors professional (at the moment), so no really in-depth questions please.
Experience Degree level education in Natural Sciences and Electrical and Information Sciences.
My final-year project was in high-voltage power MOSFETs.
Currently work for ARM Ltd, designing microprocessors.
Question this is a sort of post a level question. there is a circuit with a diamond of resistors (R1-5) and one in the centre: a bit like a triangle and its reflection in x axis
Answer You are correct in thinking that you need Kirchoff's Law
The way I would do it is this:
(Conventions: I2 = current through R2, Va = voltage across R4, Vb = voltage across R5, V = 10V).
Use Ohm's Law on each resistor:
(V-Va) = R1.I1
Va = R4.I4
etc.
Use Kirchoff's Current Law at each junction:
I1 = I3 + I4
I2 + I3 = I5
i = I1 + I2
etc.
Solve the resulting equations for i. This is merely an exercise in maths - which I have yet to find time to complete, it gets a little complex. Sorry.