12DC Sockets

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Glad you stayed on the case CBB

So a transistor acts like the switch wire on a relay

The ONLY purpose of said pcb is a learning tool, i know what it does, I'm more interested in why & how components do what they do, with intention of disecting them at the end to see the inside workings of each one so I can see how they work

It would be great to understand schematics, sure I'll get there

Teaching/passing on knowledge is classed as showing off in America?

Only joking, I get lots of strange looks & q's of long I'm going to be on computer.lol
 
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[QUOTW=]So a transistor acts like the switch wire on a relay[/QUOTE]

Yes, it can act as a switch, i.e., simply on or off. But additionally, it can act as a variable switch, if you will. It can turn on a little, or a lot, or anything in between, sort of like a dimmer.

with intention of disecting them at the end to see the inside workings
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Exactly. A man after my own heart.

It's not enough to know that a watch tells time: I gotta know how it does it.

What fun that can be...
 
My comments.

There is a lot of things to be learned about reverse engineering, moreso than just troubleshooting and building. In fact, you almost have to now days because of the lack of information. The gizmo brand wasn't even mentioned, so there is really no way to connect the dots from schematic to product. For a product such as that it will likely not even be cost-effective to build the circuit without utilizing major economies of scale. Reverse engineering can also reveal shortcomings as well. There is no intent. It is for personal use. I doubt there was a notice that "It's unlawful to reverse-engineer this product" etc like there is in software. There is probably no (c) notice on the board itself. I'm not a lawyer. The exercise is a good learning tool. I learned to troubleshoot circuits before I built them and before learning how to design them. I could have been 10 years old when I started playing with electronics.

CBB is doing a very good job here and so, seems Muttley. I'll stick my nose in once in a while.

---

As for resistors, there are 5 band resistors that have 3 significant figures and a multiplier rather than two. Tolerance is an optional band. I don;t see bandless (20%) tolerance resistors these days. Nor do we see resistive line cords that some old radios had.
 
cowboybob said:
Yes, it can act as a switch, i.e., simply on or off. But additionally, it can act as a variable switch, if you will. It can turn on a little, or a lot, or anything in between, sort of like a dimmer.
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Cool, quite a neat little component then **broken link removed**

cowboybob said:
Exactly. A man after my own heart.
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Seems we have lots in common, I like being curious, my dad always taught me that 'other people can do things we cannot purely because they have learnt how to & we haven't'
I'm hoping to have a sound grounding on basics so hopefully projects are easier & that comes with seeing whats what **broken link removed**

cowboybob said:
It's not enough to know that a watch tells time: I gotta know how it does it.

What fun that can be...
Click to expand...

**broken link removed**

KeepItSimpleStupid said:
My comments.

I doubt there was a notice that "It's unlawful to reverse-engineer this product" etc like there is in software. There is probably no (c) notice on the board itself.
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There was no anything like that **broken link removed**

KeepItSimpleStupid said:
The exercise is a good learning tool. I learned to troubleshoot circuits before I built them and before learning how to design them.
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Sounds like a very sensible way to go about things to me

KeepItSimpleStupid said:
CBB is doing a very good job here and so, seems Muttley. I'll stick my nose in once in a while.
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**broken link removed** to both kiss for having great attitude to learning & CBB for teaching me

KeepItSimpleStupid said:
Tolerance is an optional band.
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I didn't know that, an if I've been told I've forgotten

sorry reply took so long, I was looking for the bow' smiley off other forum I use **broken link removed**

easy questions for tonight then, the wires that protrude out of components, cathode & anode, they are quite long on new components, how short can you cut them or doesn't it matter**broken link removed**

When you read fuse specs, take these for instance why does a 250mA fuse have a 35A break capacity or is that just for AC **broken link removed**

So now we can carry on with learning on board, I'll desolder resistors tomorrow, will the meter read ohms off it's own battery then?

Then hopefully I can try schematic as I've downloaded a trail version of circuit wizard, so I'll not only get to try schematic, but get to try product at same time, two firsts on same thing **broken link removed**
 
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Fuse:

Note it says x to y, in other words the range of values available.

Fuses and circuit breakers are complicated little components because of ratings, trip curves, type (i.e I^2T or semiconductor fuse, fast blow, slow blow, normal blow, voltage ratings etc. Load protection is another topic all to itself. Because of capacitance and inductance, initial currents can be quite high in some instances. Time delay fuses are specified in this case. Standard run of the mill protection, the normal blow is chosen. Sometimes a fast blow fuse is needed.

A microwave usually has a ceramic fuse basically because of the large number of surges when the magnatron is turned on and off such as 10% power.

Watch out for 32 V rated fuses. Don't use them in a line application. A high voltage might arc across the 32 V rated terminals.

The major application is short circuit protection. The problem with that is that "Consumer A" or "consumer B" can change all of that by replacing the fuse with something that fits.

There are semiconductor fuses which are rated in (I^2)*time. They try to protect the semiconductor like triacs.
 
easy questions for tonight then, the wires that protrude out of components, cathode & anode, they are quite long on new components, how short can you cut them or doesn't it matter
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Lead length is generally unimportant. The leads only represent teeny resistances that have no appreciable effect on a circuit.

The only components that have a cathode or an anode are devices that have a restricted current flow direction. By that I mean devices like batteries, diodes, transistors (sort of limited to Emitter/Base considerations), electron tubes, etc.. Plain old resistors, non-polarized capacitors, wire, etc., do not care which direction the current flows in them.

why does a 250mA fuse have a 35A break capacity
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The first number (250mA) capacity is the maximum current the fuse will pass before "blowing" or opening. The "Breaking Capacity" is the maximum current the physical shape, size and construction of the fuse can handle (once blown) that prevents the TOTAL current available in the circuit to "arc or flash" across the fuse body, thereby obviating the blown fuse and zapping the circuit the fuse was meant to protect. A long answer for a fuse capacity specification that normally is not a concern. 250A at mains (youre's, 220VAC) represents 55,000 watts of power.

I, for one, don't mess with that kind of juice.

will the meter read ohms off it's own battery then
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Yes.

And Circuit Wizard will be fun, once you get the hang of it.

Enjoy, Graham.

73s

CBB

EDIT: Just noticed KISS's info. Take note. His stuff is solid.
 
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Ok I knew fuses were going to mean more learning

Going to call it a night for today, nearly the end of a long week at work & I'm shattered with cold weather, good news is that I'm only working Monday next week so we should finally make first project by then, then I can order parts & finally have first go at playing. Yippee
What's the betting I stall & it takes another two weeks to get schematic together.lol

More support CBB on your board thread

Things are looking up, this is a great forum with great people, I'm humbled to know you all & would just like to say thank you for all your support

Best Regards
Graham
 

Long but as good as always, thanks CBB & you know how curious I am. lol
There's no point knowing half a story
 
KeepItSimpleStupid said:
The major application is short circuit protection. The problem with that is that "Consumer A" or "consumer B" can change all of that by replacing the fuse with something that fits.
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So I finally know why my first multimeter melted about two years ago.lol
I never put gnd to earth while trying to read amps again *he he*
 
Muttley:

Under "Go advanced", you'll find some of the emoticons and also the ability to post certain types of attachments.
 

Edit: morning CBB **broken link removed** excited, me, what gave you that idea **broken link removed**

ok, I couldn't wait for breakfast, I'm starving now, but straight out into garage this morning **broken link removed**
I'm getting really good at desoldering components **broken link removed** I might even try soldering a few back on as it would be good practise, anyway, heres what readings I got, at least I got to use ohm reading, didn't even know what it was for before this, another first **broken link removed**

R1: 1.7 kohms
R2: 1.95 kohms
R3: 1.77 kohms
R4: 2.4 ohms
R5: 15.06 kohms
R7: 2.45 kohms
R9: 120 ohms

So I did good apart from R5 where I was way off, where did I go wrong **broken link removed**

edit: the only thing I can see looking again is if Im mistaking voilet for brown, maybe I need to get my glasses checked **broken link removed**

so, if I find out these npn's, on schematic, do you have to have right part numbers for them or am I ready to have a go now
 
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Muttley600 said:
**broken link removed**
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ok, looking again at:

A733 = NPN transistor

**broken link removed** **broken link removed**....deffo need to get glasses checked **broken link removed**

look under datasheet download link **broken link removed** = To 92/ PNP transistor

S8500 is S8550D but this is the only thing that looks like it, TO 92 SS850

Can't decide if last one is NPN or PNP **broken link removed**

Help would be good here **broken link removed**

That should make things easier **broken link removed**

We are so close

Edit: Gotta get ready for work, be back later, let me know if you find out if last one is NPN or PNP Edit again, I really gotta go but I've just found it, it's PNP **broken link removed** Hope that helps CBB, even if you get schematic sorted I'll still have a go to try new program
Have a good day

Edit: what is the difference between a NPN & PNP transistor then?

Halfway through washing up, it isn't something silly like +-+ & -+-
Which would mean dependant on which way you built circuit?
 
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OUTSTANDING, Muttley600 (we all know who you are...)!!

As far as the transistors, initially the primary info is whether it's NPN or PNP, primarily so you can use the correct designator in a schematic. The individual properties of the transistor(s) matter, but that's for later.

what is the difference between a NPN & PNP transistor then?
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The only difference that matters is in the direction of current flow through the device: NPN - emitter to collector, PNP - collecctor to emitter (Yes I know hole theory dictates the exact opposite but I don't care). For NPN the collector is assumed to be the + terminal, for PNP it is the - terminal.

ok, I couldn't wait for breakfast, I'm starving now, but straight out into garage this morning
I'm getting really good at desoldering components I might even try soldering a few back on as it would be good practice
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Man, don't I know it. The first kit I ever built was a Knight Kit "Space Spanner", superhet tube type multi-band SW radio. I had so much fun, I took it apart (every component and part), down to a bare chassis, and then rebuilt again. Did that (if you can believe it!?) five times.

Tech head HEAVEN.

So, solder and de-solder and solder again to your heart's content. You'll give up eating.
 
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Know who I am?
In a good way I hope.lol

Just realised R4 was wrong as well.....sigh

Never mind, I'm going in right direction
 
Just realised R4 was wrong as well
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R4 codes at 2.2 ohms (22 times 0.1 = 2.2). You say you got 2.4 with the ohmmeter.

That looks close enough to me...
 
I was meaning I band coded it at 220ohms instead of 2.2kohms it's that blinking decimal point again.lol

Ok, next thing has to be understanding values on caps
What do I need to know????
 
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Ok, next thing has to be understanding values on caps
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There are 2 basic capacitor types we'll deal with at this point: electrolytic and non-electrolytic.

Electrolytic capacitors are generally clearly marked in a non-coded fashion, i.e., their actual value and DC voltage limit. For example, "10uF 100VDC". They have clearly marked + and/or - leads or at least a band on one side or a band around one end marking the negative lead.

Non-Electrolytic capacitor values are a little trickier to ID. They are coded in a fashion similar to resistors, i.e., two digits and a multiplier, but there the similarities end.
Occasionally you'll see caps with color codes as well, but very rarely and most often in older gear.
Most have a NON-COLOR code of numbers and assume that MOST (but not necessarily ALL) values derived are in Pico Farads (1/1,000,000 of a Farad, or 1/1,000 of a uF [micro-farad] or 1,000 times a nF (nano-farad):

Now, rather than spell out the coding, I'm going to suggest you go to the site below. It has a capacitor value calculator (and it's UK based, so probably will be better to use).

https://www.electronics2000.co.uk/calc/capacitor-code-calculator.php

Play with the numbers.

CBB
 
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