TALKING ELECTRONICS
Interactive
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These "Discussion" pages let you know how we have structured this site, as well as provide answers to the numerous emails we get each day.
The site not a collection of "odd projects" and "ideas" that lead no-where.
It has been developed from resources that have been built-up over a period of 20 years by a teacher of electronics, Colin Mitchell, who has had his own electronics design-and-service business and employed staff to manufacture all types of electronic products.
During this time Colin has written 25 electronics books containing projects for the hobbyist and articles to help you understand the "jargon" of electronics.
This site contains many of these projects as well as a number of new designs. They all "dove-tail" into each other to build a library that will help you enormously when creating your own projects.
All you have to do is work your way through the pages and "electronics will come alive."
If you have ever wanted to pursue a career in electronics, now is the time. The projects start at the beginning with simple designs and take you through to microcontroller applications.
Electronics is one of the most enjoyable fields you can experience and can offer a life-long career.
Colin Mitchell has never "gone to work" in his life. "Work" has always been an interest, a challenge and an enjoyment.
By taking up electronics, your life can be filled with an interesting career that makes it a pleasure to be involved in.
The range of areas is enormous, from low-voltage, consumer, industrial, servicing, design, analogue, digital or programming, to name a few.
No matter what your areas-of-interest, electronics can find an application.
Our website offers the first "stepping-stone." It gives you the "feel" of electronics and lets you know how it works.
All you have to do is put a project together and feel the sense of achievement.
If you like handling small components and soldering, you have found your niche.
If you can "see" how a simple circuit works, you are well on your way to understanding the things we will be presenting.
How much do you know about electronics? Click Here for a 50 question test.
SITE STRUCTURE
Before we talk about
specific sections of the site, the first thing you should learn is
the "Art of Soldering."
We have
articles and "do-nothing" projects that
teach the art of soldering, as well as surface-mount projects and
kits
to help you solder these tiny components.
This is the way electronics is going. Surface-mount assembly is faster,
cheaper and smaller than conventional through-hole design and eventually
conventional components will dry-up from the market.
Until that time comes, we can take advantage of both types of components
and enter the wonderful world of electronics.
The first skill you will need to master is soldering.
All POPTRONICS Interactive kits are supplied with fine solder and
this is one of the most important items to improve your soldering
skills. Fine solder improves your workmanship 100%. It does this by
allowing you to feed a smaller amount of solder onto your iron and
creates a much smaller connection.
And here's a point no-one has ever mentioned before: If you add solder
to a connection while the board is almost upright, the amount of solder
remaining on the connection will be less than if the board is placed
flat on the work-bench. This is one way to create very small
connections.
The other essential item is a soldering station. It doesn't have to be a
station, but the soldering iron must be temperature-controlled and you
must have a holder for the iron. It's absolutely disastrous to have a
soldering iron floating about on the work-bench.
It really boils down to a soldering station as they are low-cost and
fully adjustable. A
suitable one is
available
HERE.
You will also need some fine
solder.
SOLDERING TEMPERATURE
Once you have a soldering iron, you will want to know how to select the
correct temperature.
It's simple:
Turn the temperature down so that the solder just melts when it touches
the tip of the iron. This is loosely called the "melting-point."
This is not hot enough. The temperature must be increased for two
reasons.
When it is increased, the flux melts faster and the joint is cleaned
more-thoroughly and the time to make the connection is REDUCED.
This is another point that has never been mentioned before. It's
actually quicker to solder at a higher temperature, and the parts stay
COOLER! That's why you need a temperature-controlled iron. You must be
able to adjust the temperature of the tip fairly precisely so the
temperature can be correctly-set to achieve quick soldering.
If your iron has a digital readout, a temperature of 325°C is suitable
for delicate work as soldering can be performed very quickly and the
components don't have time to heat up.
Each connection should be soldered as fast as possible. It should be complete
within one second. If you push each component against the PC board with
your fingers, you should not get "burnt fingers." This is the
simplest and easy way to make sure the components are not getting
damaged.
Many components can withstand high temperatures for a few seconds
but some are easily damaged. LEDs can lose their brightness, transistors
can lose their gain, electret microphones will become "noisy,"
and air trimmers will melt at the slightest increase
in temperature.
By holding a component, you are adding a heat-sink and reducing the
temperature rise.
CONSTRUCTION
Now we come to the construction-side of things.
There are two areas.
You can start with simple projects or look at our Test Equipment
section.
All our projects are built on fibreglass boards with an overlay
(component identification) and solder mask. This means
only the solder lands are visible and this prevents solder spreading to
adjacent lands. The lands are also pre-tinned to help with a quick
connection.
However it is absolutely impossible to make a quick solder-joint without
the assistance of flux.
The flux cleans the lead and the land to create a shiny connection. It
also helps to make the final connection very small in size.
If the iron is a little hotter than you think it should be (as we
suggest), the connection is also kept very small. By tilting the board
as mentioned above, the connections are also kept to a minimum.
When you are fitting the components, add only one or two at a time and snip the leads after soldering.
Never snip the leads before soldering as you may snip them too short and
they won't get connected.
Don't bend a lead more than 45° as this makes it difficult to snip. It
also make the component difficult to remove, if it needs to be replaced.
This is just the start to learning how to solder.
All you have to do is develop your skills by putting a project together.
Once you are confident you can put a project together without "lifting
the lands" or damaging a component, you will want to put more of
them
together. It's just a matter of starting.
Colin Mitchell,
Editor
TALKING ELECTRONICS Interactive
I consider it is one of the most important topics of today. The cost of energy is the controlling factor for almost everything we do. At the moment it is in the hands of big monopolies and they are making enormous profits from everything they provide.
Don't forget, profits come after all the exploratory expenses and running costs.
Energy costs are spiraling and if you want to start to analyze inflation, this is where to begin.
There is absolutely no justification for oil rising from $22.00 per barrel to more than $125.00
Fortunately, during the recession it has dropped to about $60.00 per barrel and this shows the enormous greed of the speculators, who artificially raised the price and kept it high.
Possibly the most important aspect of the world's sustainability is the use of its natural resources and the re-cycling and disposal of waste products.
This is a very involved discussion and I only want to cover a very small part of it, we shall call:
THE COST OF ENERGY
There has been a lot of discussion about the cost of "conventional" energy, the cost of alternate energy and the cost of "free energy."
First of all, nothing is FREE!
I am still waiting to see the car that runs on water.
The presenter of a seminar said a "water car" was sitting outside a lecture theatre and 5 of his friends went outside and looked under the bonnet.
I asked: "Did you take a photo?
"No."
Did you get the licence-plate?"
"No."
"Did you ask the driver to come to our meeting?"
No."
Water technology is still a SCAM, just like the Roswell invasion by extra-terrestrials.
Don't believe anything until you see it.
And then you can still be tricked.
Take the example of the con merchant who fooled investors with "TV down the telephone-line" SCAM. (This has recently come to fruition - but certainly did not exist when the scam was perpetrated).
He had a camera in one room, connected to a box and phone line.
In the other room he had the phone line connected to a box and TV set.
Sure enough, the signal was coming through and the picture was perfect.
So the investors bought into the SCAM.
Later it was found a very fine fibre-optic cable was added to the mains cable of the camera and TV.
The signal never passed down the phone line!
The scam was so simple, but no-one picked it up.
My friend lost $50,000!!!
So, you can forget about anything that looks "too good to be true" - things like FREE ENERGY don't exist.
But alternate energy does.
Before you rush into "saving the world," consider the cost to the environment, of producing items needed to produce alternate energy. This can sometimes outweigh the cost of simply burning coal, oil or liquefied gas.
In this article we will look at the the real cost of producing all types of energy and leave it to you to "consider the costs."
Everything we do will be referenced to a known consumption - a 1kW radiator bar. We all know how effective a single bar radiator is.
It will heat a "standard room" (3m x 3m or 10ft x 10ft) with 8ft ceiling (2400mm) and when it gets to 22°C, it will stabilize at this temperature, if the outside temp is about 15°C. This means the heat-loss equals heat-input and at 22°C, the heat losses of the room equal a constant rate of 1,000 watts.
Furthermore will say that it takes 1kW to produce 1HP of work from an electric motor as the efficiency is about 80% for small motors. For larger motors the conversion factor is 746 watts equals 1 HP.
Now we will cover the cost of "conventional energy" ELECTRICITY and GAS, as supplied to a standard house in Victoria, Australia in 2008.
These figures do not include "Service charges" etc.
| ELECTRICITY | 17c per kWHr |
| GAS | 5.1c per kWHr |
| BBQ GAS | 20c per kWHr |
In other words, a single radiator
bar using electricity will cost 17c per hour or 5.1c if it is powered by
gas. Bottled gas, called BBQ gas, is the most expensive, as it has a
"filling cost."
Electricity is 100% efficient. There are no flue-gasses or
losses.
Gas is 75% efficient as about 25% of the energy goes up the flue as
"gasses of combustion" when used in central air-conditioning.
Gas is quite often used for "burners" in "cook-tops" as it is
"instant-heat" and can provide more energy than electricity.
An electric element is limited to 2400 watts whereas a small gas burner
is 1.1kW, medium is 1.8kW and large is 3.1kW. A Wok burner is 4.2kW.
Clearly, this amount of output cannot be provided by an electrical supply.
You quite often see the output of a gas heater as BTU per hour
Our hot water service is 42,000 BTU/Hr (this is called an input-value)
Our central heating is 120,000 BTU/Hr (input)
| 42,000 BTU/Hr | =12,300 watts | 75% efficient | =9,200 watts |
| 120,000 BTU/Hr | =35 kW | 75% efficient | =26kW |
A 42,000 BTU/hr hot water heater
will produce 120 litres of hot water in one hour (this is allowing for
75% efficiency and water raised from 15°C
to 80°C.
We have not taken into account losses from the tank due to poor thermal
insulation).
Instant hot water heaters are slightly more efficient (stated as 95%),
but the largest unit has an input of 152MJ/Hr (42kW) (142,800 BTU/Hr)
and this can produce only 24 litres per minute with a temperature rise
of 25°C.
Incoming water is generally approx 12°C,
so the output is really only 18 litres/min as the water from the head of
the shower has to emerge at 44°C
for a shower at 42°C.
The water looses 2°C
in falling. This hot water unit is suitable for a 12 litre per
minute shower, but hopefully no-one else in the house will turn on a tap
when someone is showering!
If a 120,000 BTU/hr central heating unit has 7 outlets, each outlet will
deliver 3.7kW
Again, this is clearly more than any electrical supply can offer.
That's why we use gas.
Cars are another factor in using fuel inefficiently. A standard petrol
car uses about 30% of the energy of the fuel to move the car. The
remaining 70% is lost in noise and heat.
An average car uses 10 litres of fuel to travel 100km. The energy from a
litre of fuel is about 45MJ/kg but a car can only produce about
17.6MJ/kg of work.
If a car travels at 100km/hr, it consumes 10 litres or 8kg of fuel.
This 8 x 17.6 = 141MJ
3.6MJ = 1kW
So the car is delivering 39kW
39kW = 52HP
On a cost-basis, the 39kW has cost the motorist $12.00 or 30cents per
kWHr @ cost of petrol = $1.20 per litre.
On a distance-basis, the cost to the motorist is 12c per km.
The actual cost of fuel (petrol) is 12c per kWHr - meaning the amount of
heat that can be obtained by burning the fuel in a 100% efficient
reaction.
The cost of LPG (Liquefied Petroleum Gas) is about 7c per kWHr. -
meaning the amount of heat that can be obtained by burning the fuel in a
100% efficient reaction.
| Petrol | 45MJ/kg | 32MJ/litre | Burn 50 litres (in 1hr) = 450kWhr |
| LPG | 45MJ/kg | 25MJ/litre | Burn 50 litres (in 1hr) = 350kWhr |
LPG has 80% the calorific value
of petrol on a VOLUME BASIS and this is how we buy each of the fuels. In
other words, if 10 litres of petrol moves a car 100km, 10 litres of LPG
will move the car 80km.
LPG in Australia currently costs 43% of unleaded petrol and since it has
only 80% of the calorific value, this equates to 52% or about half the
cost of unleaded petrol on a mile-for-mile basis.
ENERGY
CONSUMPTION
The only way to work out the overall cost of energy in a household is to
work out the ENERGY CONSUMPTION per day.
We will take the example of a single person. For two people, add 20% and
about 10% for each additional person.
There are 5 energy requirements: Heating, lighting, hot water, cooking
and appliances.
We have already mentioned the cost of heating is 1kW for an "standard
room." If the room is heated from 5pm to 11pm, the consumption will be
6kWHr.
We will allow a total of 1kWHr for lighting per day.
A 10 minute shower using 11 litres per minute will use 110 litres of
water. 50% of this will be hot water, requiring an input of 4.5kWHr.
Cooking will require 1kWHr
Fridge, washing machine, kettle, micro-wave oven will consume another
2kWHr per day.
The total minimum is: 13.5kWHr per day.
This is an average of 600 watts continuous but the demand comes in
bursts and this could be as high as 5kW for a short period of time.
That's why a household needs three different forms of "renewable
energy."
Here are 5 different "low-cost" energy solutions:
1. Wind generator
2. Water turbine,
3. Solar heat box,
4. Solar pipes on the roof to heat water,
5. Solar cells,
6. Wood fire
7. Bio gas.
The biggest problem with all forms of energy generation, is storing or
producing the energy when required.
The problem is to store it during the day and use it at night, or to store it
from one week to next or from one season to the next.
If we could store the solar energy that reaches our roof, we would all
be millionaires. A typical roof on an 18 square house absorbs over
450kWHr of heat on one sunny day!
If this could be converted by a heat-pump to high temperature energy and
stored in a water-tank or heat-bricks, we would never need to buy energy
again. A simple steam turbine could be used to generate electricity and
we would be self-sufficient for ever.
But this is sadly not possible for everyone. That's why the energy utilities are
using us as "piggy banks."
Electricity is supplied to Alcoa (an aluminium manufacturing company) for 3.5c per kWHr and Liquefied Natural
Gas is supplied to China for 5c per litre.
Our relative costs are 17c and about 75c.
This brings up two points. If we paid less for electricity and gas,
would we use more? If we paid less for energy, would be invest in
"alternative sources?"
Don't get hooked on the carbon dioxide debate. Carbon dioxide comprises
only about 0.03% to 0.06% of the content of air and it has only risen 0.001% in the
past 100 years.
It is a contributing factor to global warming but when you realise the
amount of heat delivered to the earth from the sun, the effect of
bush-fires and things like steel production, the contributing factor of
households is miniscule. Look at the wasted street lighting and office
lighting at night-time.
Freeways could have the lighting triggered by vehicle movement so that
whole highways of lighting could be turned off when no traffic movement
is detected.
Now we come to the point of being
able to produce energy by some lower cost.
Unless you have a thermal geyser under your property, the only three
inputs you have available are: wind, sun and water.
One of the most popular methods of generating electricity is wind.
It has been proven that a large wind turbine can produce about one
megawatt of electricity on a fairly constant basis when the turbine is
placed in a windy location. The recent debate of their ugliness
has been overturned and the disgusting fraud perpetrated on the industry
by nature conservationalists has been exposed. They predicted birds
would be killed when they flew into the blades (turning at 20rpm!) and
sure enough, dead birds were found on the ground soon after the turbines
were installed. So the authorities installed cameras and found the
conservationalists were dumping dead birds during the night!
When you get up close to a 30 metre tower ad see the revolving blades,
it is certainly a sight to inspire. The turbines are only a few hundred
metres apart and a few acres of land can generates 15 megawatt.
The only deterrent is the cost of installation and this will come down
when they are mass produced.
For the individual householder, a small generator may be the answer. But
when you find out the maximum blade diameter allowed is 1.2m you will
quickly realise the maximum generating power is 1kW. The law will have
to change
The cheapest type of generator is water. For any type of water turbine,
it will operate 24 hours a day.
The diagram below shows a water turbine that produces 200watts of power with only two feet of head
and a Kilowatt of power -- enough to completely power an average
household -- with only 10 feet of head. The design uses a very clever
"draft tube" to take advantage of the falling water and thus draw the
water through the blades of the turbine. The second photo shows the unit
on a wooden seat. The "draft tube" is clearly seen. The third photo comes from a company based in
Jakarta, Indonesia. They represent manufacturers from Europe, US
and other Asian countries. The two generators look very similar.
The US company sells the generator for US$2,200.
Suppose it lasts for 8
years and produces 24kWHr of electricity per day.
The cost per kWHr will be 3.1 cents.
Another type of water turbine is shown in this movie (1MB). The diagram below shows how the blades are turned so they do not present themselves fully to the oncoming water. This provides a much-greater area to the flow of water in the forward direction but introduces a number of joints at the top and bottom of each blade, that need to be protected from wear. A much simpler and more efficient solution is to mount the turbine transverse on a barge so that only the lower half of the drum presents itself into the water. In this way the returning blades would not be forced against the flow of water. The shaft could also be taken to an in-line gearbox to increase the rpm about 7 times and the output from the size presented in the 10 second movie would generate about 5kW. Installation costs would also be reduced enormously. The diagram below shows how the vanes turn to reduce the force against them when they are returning. A very clever idea but quite complex.
The cost of a 1kW design is $5,000 plus $5,000 for installation. The
projected cost for the electricity produced over a 10 year period is
50c per kWHr as per the website.
This invention can be found at:
http://www.sundermann.com.au/index.html
There are a number of other designs including an under-water model shown
in the photo below. It will produce 100 watts in a fast-flowing stream.
By far the best place to look for any items associated with renewable
energy is on eBay. Suppliers and manufacturers are very reluctant to
provide prices, whereas eBay gives a huge choice of items and prices.
Similarly, a search for articles on renewable energy via Google will
provide you with a huge range of options.
After searching the web for some considerable time, the following
figures were found for power generation from water and wind.
It can be clearly seen that the power available from a simple water
turbine is much greater than a wind turbine due to the density of
water.
The formula is:
Power = ½ p A V3 watts
where p the density of water, A the area swept by the rotor blades and V the stream velocity. The marked difference in power generated by water compared to that of wind, however, may be seen from the table for various velocities assuming a density for water of 1000 kg/m3 and an air density of 1.2473 kg/m3 corresponding to air at 10
°C.|
Velocity |
Water kW/m2 |
Wind kW/m2 |
| 1 | 0.5 | |
| 2 | 4 | |
| 3 | 14 | 0.2 |
| 10 | 5000 | 0.6 |
| 15 | 2.1 | |
| 20 | 5 |
A stream of water flowing at 10 metres per second has the potential
to generate up to 5 megawatt of electricity for a simple paddle
measuring one square metre! We can only get a maximum of 60%, but even
if we could only get 1%, it would represent 50kW!
There is much more energy in a flowing stream than we have ever been
told and it will just take someone to produce a simple paddle wheel
connected to a pulley to drive an intermittent pulley that drives a
final pulley on a generator. The two stages of drive are needed to get
the rpm up to about 1000 rpm to make the generator efficient.
A single v-belt will transmit about 5-10HP so you will need a pulley at
each end of the paddle and two or four 5kW generators to get
enough for a dozen houses or so. All the merging of the output of the
generators can be done with electronics and it's just a matter of
fabricating the paddle on a barge.
This type of power generation plant will not upset the flow of any river
as no dam needs to be constructed. The barge is held to the bank with a
pole on a loop and will rise and fall with the river. The barge is also
tied in position with guy wires.
All this can be done for less than $10,000 and the electricity supplied
at about 5c per "unit."
Surplus electricity is passed to "dummy loads" consisting of heaters in
a water tank. In this way the system heats water for the household as
well as all the other requirements.
While on the topic of energy conservation, we hear a lot about "saving
the planet;" buy high-efficiency globes.
Our local council is providing a FREE change-over service. They will
change all your "inefficient incandescent globes" for Compact
Fluorescent Lights.
But have you considered the amount of energy required to manufacture
all the components in a CFL. The picture above shows the enormous number
of components required to produce the high strike-voltage and
current-limiting once the tube has struck.
What is going to happen to all the good globes that have been replaced!
What is going to happen to the CFL lamps when they eventually fail? What
is going to happen to the tiny amount of mercury gas if the lamps get
smashed?
Most of the CFL lamps fail prematurely due to heating and drying-out of
the electrolytic and faulty solder-joints. Most do not see the predicted
"9-lives." The reason is the lamp is mounted up-side-down from
the ceiling and the heat from the lamp rises and heats the electronics.
This was never taken into account when the lamps were "soak-tested."
What is the point in saving a few watts when Australia is supplying
China with millions of tons of coal each year? The ships are lined up at
the wharf, 24 hours a day waiting to be loaded. Each kilo of coal
produces 2kg of carbon dioxide.
What about looking at the city with the lights in every office burning
24 hours a day. What about looking at the lighting under bridges. If you
count the number of 500watt bulbs per underpass, you could supply 100
houses with electricity.
No. It's all a myth. We are not "saving the planet" and no amount of
conservation will overcome the enormous amount of degradation taking
place by the multinationals. Not that they are to blame. It is the
consumer that wants everything wrapped and presented in an attractive
way. It is the consumer that "half-uses" everything and throws the rest
away.
You only have to look at hard-rubbish collection each year. Nearly every
house has a TV, microwave oven, chair, lounge, BBQ, VCR or computer to
be picked up. And the next year the pile is even greater. Our houses are
absolutely stacked to the ceiling with devices we use as well as devices
ready for the tip.
You have to remember one thing. Every shipping-container of product that lands on
your shore will have to be dumped in a tip at some time. Our
sea-terminal gets 500,000 containers per year. Multiply this by the
number of terminals in the world.
What is changing 20 globes going to do to conservation?
Think of it in fractions of a millionth of one percent.
One interesting thing that has come from LED technology is the improved
clarity and truer colour produced by LED street-lighting. The photos
below seem to show the improved appearance from LED lights, over the
sodium lamps. I have not seen the improvement myself. The LED
lamps use approx 50% less energy.
