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Friday, 19 October 2012

Be thankful of AC transmission line

Recently I came across some pictures during Edison’s day, where the power line was in DC. Since there are lots of power loss (see Why Transfer Power At High Voltage), lots of cabling were required for power transmission. And the end result? Below is the picture that I managed to Google. At that time, in some part of the city people literally cannot see the sky!
Picture from wiki :

Sunday, 14 October 2012

Impedance matching–What does a mountain bicycle has in common with a transformer

As a cyclist and a transformer user, can’t help to notice the similarity of the two. So below is the picture of a mountain-bicycle and transformer taken from my favourite source Wikipedia.

To compare them, look at the table of comparison below:
A Bicycle A Transformer
number of “teeth” of sprocket number of winding
front sprocket primary winding
rear sprocket secondary winding
gear chain transformer core
now, isn’t this amazing?

To understand sprocket, visit

Pictures from :

Friday, 5 October 2012

Getting to know simulation - Part11 - Monte Carlo

To best illustrate the usefulness of the monte-carlo simulation, let’s use a voltage divider as example.
Run Transient simulation and get:
So this is a perfect voltage divider. But we all knows that resistor has tolerance, let’s say each of R1, R2 has 1% tolerance. We should factor this in by running Monte Carlo simulation and see what are we dealing with.
Enter 1% as the resistor tolerance.
Tick “Enable multi-step” to enable Monte-Carlo analysis

Set number of runs to 100
Re-run the transient simulation to see gain statistic of  divider made of 2 pieces of 1% resistor.
With resistor tolerance of 1%, the voltage divider will give an error of ~-0.9% to ~+1%. Use of Monte-Carlo simulation will ease such analysis. If your application cannot tolerate such variance, then resistors with better tolerance are needed.