Archive for the ‘Uncategorized’ Category

Electronics Made Simple

Thursday, June 25th, 2015

If you grasp a few simple concepts then making your own electronics gadgets is not that difficult. I am assuming that you understand simple concepts like resistors and ohms law, capacitors, etc. There are a few simple building block in electronics

Is my mobile phone killing me?

Thursday, June 25th, 2015

This is a concern many people have and they get very anxious when they hear there is to be a mobile phone mast to be located near them.

Electronics Made Simple Part 2

Thursday, June 25th, 2015

Using on the simple circuit we discuss last time, we can make a simple microphone preamplifier by connecting two of the simple amplifiers together.

Near Field / Far Field

Thursday, June 25th, 2015

In the last blog I said that I would talk about near and far fields. When you have a tiny antenna you radiate in all directions. Some signals are going around the antenna and others are going out from it. Depending on the construction, the electric and magnetic components fall off at different rates in different directions. . The components decrease by different amounts depending on the distance from the antenna. Some at 1/r, some at 1/r2 and another at 1/r3 . The distance from the antenna at which the various components are all equal is defined at the boundary between the near and the far field. This happens to be λ/2π. Where λ is the wavelength of the signal. The near field is often also called the reactive field because when you are in that area you are also affecting the source of the signal i.e. you react with it.

Hot Water for Free?

Thursday, June 25th, 2015

The thought of hot water for free, seems too good to pass up.  I decided to install a solar collector on my roof.  As the back of my house points due South, it is the perfect location.  For all new houses, it is a requirement that 60% of their hot water should come from solar.  While the thought of free electricity seems even better, the cost of installing a photovoltaic (PV) collector is astronomical.  Also the conversion efficiency is much lower, so you would probably never achieve a payback on your investment.

Starting with electronics

Thursday, June 25th, 2015

I’ve been teaching electronics to adults for a few years now and I get confronted with the same difficulties every start of the year. How do you get the basic understanding across to people who have totally different professional, educational and socio-economic backgrounds?
There isn’t a guaranteed recipe. What I try to do with more or less success is to relate electricity concepts back to something they all know:  water!
You what? Yes water, it’s not the perfect analogy but it gets the idea across and people seem to grasp things easier.

But how?
Well voltage is similar to water pressure. You can have a high pressure but no flow.

The voltage divider

Thursday, June 25th, 2015

The voltage divider is probably the most common circuit element around. Although it appears to be very simple in principle there are a few things to remember when using one in a practical application.

The following circuit gives the structure of the voltage divider.

From idea to circuit board

Thursday, June 25th, 2015

For the electronics enthusiast wanting to create his own designs the traditional way was to draw the schematics on paper and then build a board with prototyping boards, a strip board or draw the PCB layout using an etch resistant PCB pen or on a transparent sheet and exposing the board to UV light and then etching it with chemicals. These are quite suitable for simple circuits. However, when it comes to using the more complex ICs such as micro-controllers, this method quickly becomes overly complex and one needs to turn to “real” printed circuit boards (PCB).
Here the choice is vast and a number of prototyping service providers can be found in every electronics magazine on sale at your nearest newsagent.