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June 07, 2023, 07:33:12 AM

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Thevenin and Norton (and you)

Started by saturated, May 10, 2023, 07:15:14 PM

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I just started another book and it is really good but they immediately had me doing Thevenin and Norton exercises.

I was like "oh no not again plugging and chugging exercises.."

but I guess i will work through it and get to the good stuff...lots of circuits...yeah  :)

I reckon knowing it will help me somehow down the line



Hey chum, unless you intend to build the next space shuttle leave that really hard stuff till later.
If all you want to do is understand Analog Audio Amps then you will learn faster by reading stuff on pages like this;

Open up Articals.
Learn some basics first mate, such as transformers and rectification then move on to basic transistor circuits.

Scroll down to *Beginners Luck*, a lot of good stuff to find there.
Stuff there will help you get your head around the basics.

Be warned you will need weeks to absorb it all as it's a massive site with heaps of good info.


I have to agree with Phil, too much theory can get in the way if you don't do a lot of practice with real circuits.

I think what would be good for you is to get a breadboard and start building small circuits like stomp-boxes and even small SS amps, and then you can modify them to see what happens in real life with the signal.

You would not need to spend a fortune on parts because you will be able to re-use all the components, just build up a common variety of parts and off you go.

A bread board needs to be a good size to start with, I would buy one with at least 800 points on it.
You can always get another one and use several breadboards for a single build if the circuit is big.
Here is a link to a well priced one: https://www.taydaelectronics.com/hardware/breadboards/830-point-solder-less-plug-in-breadboard.html

I get most of my components from Tayda, if I order resistors I get 50 at a go and then slowly order more values as I need them.
any components that are regularly used I order multiples of them, and if there are better ones for the same price I get the better ones.
One part comes to mind, 1N4001, 1N4004 diodes are used a lot, I get the 1N4007 instead as they have a higher voltage rating but are the same size and price.

There are no stupid questions.
There are only stupid mistakes.


One of the things you do in early electric/electronic class is learn how to analyze simple circuits usually with a battery, a switch or two and several resistors or light bulbs. You learn how to apply Ohm's Law to calculate Voltages, currents and equivalent resistances. If you skip this step or don't know how to do it, you can look pretty stupid on an internet forum.

Do you know how to hook up a light bulb so you can flip it on of off from two different switches no mater how the other switch is flipped ? How about three switches ?


well guys you got me

I tried to put the three switches in parallel and that works for any one of them turning it on
but none can turn it off

and then the opposite if i put all three in series..

so then i started drawing different combinations progressing to a delta and or wye

so no i dont know.....

but i dont want to cheat and look it up

so I will continue to work on it while watching hockey



Quote from: Loudthud on May 11, 2023, 02:45:12 PMYou learn how to apply Ohm's Law to calculate Voltages, currents and equivalent resistances. If you skip this step or don't know how to do it, you can look pretty stupid on an internet forum.

Yep,  I'm laughing cause That describes me very well.  :-[ :D
Yes I do have times when I get stuck and have to go back and refer to books to recall even basic ohms laws.
I figured I was too old to go back to school so I cheated and just use sims to workout most of the maths.

I use sims and the breadboard to design build my own circuits.
Being able see a graphical plot on the screen at any point in the design makes it so much easier to work out just where you win or loose the mojo.
I can't afford scopes and other fancy teck bench gear and as most of the gear I build is fairly straight forward it's not worth spending on gear that will not get much use.


I was thinking it's kind of hard to learn those circuits out of a textbook, I learned them from an instructor with a chalk and blackboard. I see an opportunity for a You-Tube series with an instructor, maybe even animated graphics.


thanks guys

Mr. Phil...you may downplay what you know and I applaud your humbleness...but I read all the old posts and you have fixed and help fixed a ton of stuff.   :)
but I get your message...

Mr. TV I have some nice Jameco breadboards and a couple nice power supplies...and have procrastinated ordering components to play with.  thank you for the recommendation on a source for them.  I have been reluctant to order because I want to make sure I get stuff that has a good diameter ample lead to use.

Mr. LoudThud I appreciate you being here to help...Im ready to look stupid as long as I learn  :)

back to the light switch question...they are all single pole switches right?



Quote from: saturated on May 12, 2023, 09:45:08 AMback to the light switch question...they are all single pole switches right?
I don't want to give away the answer, and I applaud your determination to figure it out for yourself, so I'll give you this: At the Home Improvement store where they sell what you need to do the trick, they call the switches you need to do the common two switch circuit a "three way switch" and the one you need to add for the three switch circuit a "four way switch". Once installed and covered up with a face plate, the switches look and feel like the normal On-Off switches you see and use every day. (These names apply in the USA, not sure about other countries.)


In Australia there would be 2 x SPDT switches and the last switch is a special 4 terminal switch called an intermediate switch made for this purpose.

If you are using normal toggle switches then you would need 2 x SPDT and 1 x DPDT switches for the 3 switches and one light.

Just imagine a really long hallway with a door in the middle and doors at each end of the hallway.
You would want to be able to turn the light on/off whichever door you go through.

There are no stupid questions.
There are only stupid mistakes.