Author Topic: Electronics tutorial  (Read 14820 times)

MJLorton

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Re: Electronics tutorial
« Reply #15 on: November 07, 2012, 07:16:58 AM »

PS: Maybe you can incorporate something similar in the next electronics tutorial, Martin. Thanks!

I did...I hope the theory works for you...

Electronics Tutorial #5 - Ohm's Law Pt 2 - Application:LED Resistor, Voltage Divider, Current Shunt
https://www.youtube.com/watch?v=AWLJADJTWHU
Play, discover, learn and enjoy! (and don't be scared to make mistakes along the way!)

birrbert

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Re: Electronics tutorial
« Reply #16 on: November 08, 2012, 08:10:05 AM »
OK. Let this be a rhetorical: how on earth did I miss part 2? :o
Let me make that up to you with a Like after I watched it.  ::)
"Dubito ergo cogito, cogito ergo sum." Descartes

MJLorton

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Re: Electronics tutorial
« Reply #17 on: November 09, 2012, 08:44:29 AM »
No prob....thanks! ;)
Play, discover, learn and enjoy! (and don't be scared to make mistakes along the way!)

angelico

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Re: Electronics tutorial
« Reply #18 on: January 28, 2013, 03:17:19 PM »
Hi Martin,

(sorry my english...)

I like very much the electronics tutorial #8 about diodes.

I dont have a waveform generator to reproduce the experiments.

But i know that is possible to do with Arduino (see attach).

Thanks very much.

Fennec

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Re: Electronics tutorial
« Reply #19 on: January 28, 2013, 03:51:53 PM »
Ahh

Why you don't use a transformer ? And for other waveforms the good old XR2206.
Or look at ebay. For under 50.- I am sure you find a useable function generator for your first steps.
« Last Edit: January 28, 2013, 03:54:53 PM by Fennec »

MJLorton

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Re: Electronics tutorial
« Reply #20 on: January 30, 2013, 05:28:45 AM »
Hi Martin,

(sorry my english...)

I like very much the electronics tutorial #8 about diodes.

I dont have a waveform generator to reproduce the experiments.

But i know that is possible to do with Arduino (see attach).

Thanks very much.
Hi Angelico

Thanks very much for the feedback and a great post. Using Arduino had crossed my mind but ultimately I wanted a reasonably good function generator for the bench. Great to know that there are options for folks to build.

Cheers,
Martin.
Play, discover, learn and enjoy! (and don't be scared to make mistakes along the way!)

bc10

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Re: Electronics tutorial
« Reply #21 on: August 14, 2013, 04:09:17 PM »
Hi,

I have some questions after watching Electronics Tutorial #1:

- What determines that a power source will produce AC or DC?
- If AC is more efficient than DC, why is DC used in automobiles?
- On the oscilloscope, when the wave goes past zero, is electricity being produced?
- In the analogy of the pipes and water it's mentioned that the power source doesn't produce the water/electricity. What does produce it?
- In the pipe analogy, it's stated that if the valve is closed there will be no flow but there will be still pressure. Would that pressure exceed the 12 volts because it has nowhere else to go and the pressure just keeps building at the valve?
- The 110v doesn't produce enough amps to operate a kettle, so a greater voltage is needed. Why then in a car is a larger battery that will produce more amps but keeps the same voltage? Shouldn't a greater voltage be needed to produce more amps? How do two different sized batteries produce different amperages even though they have the same voltage? Sometimes even the same sized batteries produce different amps.

Thanks,
bc10

OAFCLomax

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Re: Electronics tutorial
« Reply #22 on: May 06, 2014, 05:25:10 PM »
Okay, I've been following the series closely and I've run into some problems I can't seem to get my head around.

When we're working out R2 in the Voltage Divider, your formulas seem to make sense. I arrived at 829.4 Ohms just like you, however I didn't really "get" the relevance of bringing in a parallel circuit but I carried on with the formulas.

What I didn't get was how 829.4 Ohms became Rt when working out R2 when R1 = 4.7K Ohms. I thought Rt = the some of all the resistance in your circuit, including all resistors.

I hope you see where I am coming from.

Cheers, Dan.

SeanB

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Re: Electronics tutorial
« Reply #23 on: May 07, 2014, 01:18:17 PM »

What determines that a power source will produce AC or DC?
Ac is produced by rotating machinery in most cases, used because you can easily transform the voltage to different levels and trasnsmit over a long distance with little loss. DC is mostly produced by batteries and generally is useful as it does not go to zero with each cycle but has both constant polarity and voltage. For a resisive load the source is not important, but many loads will stop working with AC as the polarity reverses.
- If AC is more efficient than DC, why is DC used in automobiles?
In a car DC is stored by the battery in a chemical reaction, and this enables you to store power for later use, like to start the car later.
- On the oscilloscope, when the wave goes past zero, is electricity being produced?
Yes, power is the product of voltage and current, and with AC into a resistive load it is always going to be positive.
- In the analogy of the pipes and water it's mentioned that the power source doesn't produce the water/electricity. What does produce it?
A pump does, like in voltage the electrons do not produce voltage but this is generated by either an external force increasing the energy of the electrons or a chemical reaction doing the same.
- In the pipe analogy, it's stated that if the valve is closed there will be no flow but there will be still pressure. Would that pressure exceed the 12 volts because it has nowhere else to go and the pressure just keeps building at the valve?
No, the anology is not exact because the pump builds up to a pressure where the flow passes back through the pump  for a centrifugal pump and for a piston pump till the force driving the pump is equal to the back pressure. This is analogous to the open circuit voltage as no current or water flows, this is the open circuit voltage or the closed pressure.
- The 110v doesn't produce enough amps to operate a kettle, so a greater voltage is needed. Why then in a car is a larger battery that will produce more amps but keeps the same voltage? Shouldn't a greater voltage be needed to produce more amps? How do two different sized batteries produce different amperages even though they have the same voltage? Sometimes even the same sized batteries produce different amps.
A kettle can be built to work on 110V, it just draws more current, and the max current is limited by the wiring. The relationship between current and voltage is resistance. A resistor can have a high value, and thus you need a high voltage to get a defined current to flow through it. A lower value resistor needs a lower voltage to get the same current. Voltage and current multiplied together gives power. You can have a low voltage and high current, or a high voltage and low current, but have the same power in a resistor. In a car battery you have the ability to deliver a lot of current, and the batteries may be rated for how much current they can deliver, this is generally given as cranking current, so that you can draw up to this current safely for a few seconds to start the car.

MK Nadar

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Re: Electronics tutorial
« Reply #24 on: May 10, 2014, 06:57:04 PM »
Hello Martin,

I just saw your first video on electronics tutorial, I immediately liked, subscribed and came to your forum.

I have got some doubts.
How electrons flow in an AC supply. As electrons experiences push and pull how can it flow from one point to another.
It has a logic that in DC supply electrons are flowing as it is just a flow of electrons.
But in AC how is it possible. I hope you understand my doubt.

I also have some other doubts.
How many electrons flow in an ampere and how it is defined?
How voltage is defined and how the pressure of electrons are calculated?
How resistance is defined and how many electrons are blocked in an ohm?

Waiting for your reply. Thank You