12DC Sockets

[Muttley600]

As I have totally 100% let go of this circuit now *grin*

I had minus voltage because my 13.7v was facing backwards, I now have normal readings after connecting R9 straight through to top gnd on its right hand side , that's what I'd missed

Let go, of course I have, lol

 

[KeepItSimpleStupid]

I still pop in from time to time.

Doesn't that schematic in post #253 have a glitch? The ammeter is the load. An ideal Ammeter has zero ohm resistance. This should not simulate well. Pick a load R = V/I

 

[Muttley600]

Hi KISS
Let's just say I'm on a steep learning curve, reckon we've just got circuit finished now, hopefully I've learnt how to use the meters today so should be able to post readings I was so curious to see tomorrow

 

[Muttley600]

Another night done, see you tomorrow
Graham

 

[Muttley600]

Morning CBB
Thanks for the file, I'll have a paly with it in a bit after chores, in the meantime, here is my scribblings of mini pcb that I took my schematic off to see if you can spot any errors, ignore labels I've dotted around outside & they have either being changed or are correct, anyways something to look at while I get sorted

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Better outline of components

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[Muttley600]

Well I guess your not going to be suprised when I say I didn't really understand anything I did on that little test **broken link removed**

So lets start with the basic stuff, why am I getting a 'V' reading of 5.6, after playing with resistor I see that looks like the case
Why am I getting a 0v reading after the zener bar but then getting a reading when I get back to the left of R2, basically the top of the circuit is dead, so how does it create the circuit

Now I am confused???

 

[cowboybob]

I'll take a look and compare to the schematic.

I've been looking over the differences between Tina V9 and Tina TI (which is V.7) of which I have both.

Pretty significant. Most notably, In TI you don't have an interactive Mode. which allows real time circuit response values.

But the "Analysis" - "DC Analysis" - "Table of DC results" at least gives you "snap shot" values. Awkward, but informative.

Guess you've already seen this.

I included the graphing option as another values observation.

Just read your post of 7:25AM. I'll edit this post with my suggestions.

 

[Muttley600]

Just read your post of 7:25AM. I'll edit this post with my suggestions.

**broken link removed** or 12.25pm **broken link removed** I'm keen but got up late as I was up in middle of night again **broken link removed**

Just what time do you get up of a morning **broken link removed**

 

[Muttley600]

Sorry I'm trying to concentrate, look at input voltage & output voltage, have we got it **broken link removed**

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I just seem to find it easier to relate to this circuit if that makes sense, I know I said I'd let it go, but that seems right doesn't it, that means I can understand this stuff, i can do it

please let that be right **broken link removed**

ok, if we change input voltage that doesn't workl as voltage regulator
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but if we were taking view that module draws same as my other one, which is around 0.1mA, look what happens

At 13.7v input
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with current
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for truck with 24volt input
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with very similar current draw
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so is it that your intial theory of it being a current regulator rather than a voltage regulator correct **broken link removed** as the module draws very little power or does it just mean that the module will work between 6-12V ?? But doing that pushes it up to nearly 2.5A & fuse is only 1A

 

[cowboybob]

Edit: 0835 - still looking. Did the sim in Tina Basic and the values match. Trying to figure out how to keep the power on after the DC analysis. If in fact that's what I'm doing.

Did the above before I saw your 0830 post. I'm gonna guess YES. Makes sense that the unit would handle over-voltage(s) at the input. But I've got to admit, don't have a clue how the circuit is doing it. At least not yet.

Still playing w/ the Tina TI "Basic zener" schematic.

 

[KeepItSimpleStupid]

A 1N4148 is not a Zener. Can you measure the voltage across Zd1 of the actual circuit in both directions?

 

[cowboybob]

Graham,

I understand wanting to get the PCB circuit figured out. Me too.

But, If I may suggest, Let's get the "basic Zener" schematic under our belt,
and how to optimize the use of some of the elements of Tina TI out of the way first.

The zener circuit, when you use the "DC Analysis" function gives some confusing results (i.e., a "0" voltage where you KNOW that it's not zero).

But first, we need to make some changes to the zener circuit:

Change Z1 from a 1N2804 to a 1N4733: (I'll explain the change later)
Change R1 to 150 Ohms
Change R2 to 2K

Now we're going to add a "Voltage pin". Go to the "Meters" tab and select the LEFT most most item (if you hold the cursor over the symbol it will eventually say "Voltage pin". and put it in the schematic window. Make sure it is highlighted (selected). Using Ctrl-R (right) or Ctrl-L (left), rotate the voltage pin symbol to orient it so that it can be attached to the right terminal of R1, facing in a direction that it's not hidden by a component. Note that it's name is VF1.

Note: ALWAYS perform an ERC (Electrical Rules Check) Analysis after making ANY changes to the schematic. It checks for bad connections (among other things) If there is a wiring problem, click on the error definition and it will highlight on the schematic where the problem is.

Now select the "Multimeter" from the T&M menu. Select the "V" (volts) button. Note the "Input" area selection (there will be VF1+ and VF!-, or an option of nothing). With additional "Voltage pin"(s). Additional options for the "Input" will be accessible.

OK, now play with R1's value (first) using the multimeter.

Let me know how it goes.

CBB

 

[Muttley600]

I am so tempted to buy another to to get load reading, yes a whole £2.49 **broken link removed** I hate being beaten, even if it's only for the sake of understanding **broken link removed** .............hold on, what am I on about I have another lead, shall I get load of module **broken link removed** means breaking the other plug open but I dont actually need the module anyway
Then why you must be asking yourself, because this seems like ace value training on tronics **broken link removed** once I've nailed understanding I should be laughing right & it seems we are soooooooo close to nailing this circuit, I even understand meters & readings now (read Amps & voltage **broken link removed**) so we are going forward

 

[Muttley600]

A 1N4148 is not a Zener. Can you measure the voltage across Zd1 of the actual circuit in both directions?

I didn't realise there were more posts, I kept refreshing last page........sigh
We could measure both sides on sim, not for real cause I've desoldered everything

In4148 is a switching diode whatever that is, does it have a different symbol **broken link removed**

Reading to left of diode 36nV
Reading to right of diode 2.25V (bar side)

 

[Muttley600]

on it now CBB, back in a mo

R2:

2k = 0V
5ohm = 0V
10K = 0V

I have got the pin in right place haven't I

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[cowboybob]

On the multimeter you have the "Input - LO" selection set to Gnd. This schematic has no Gnd, as such.

Either select "VF1-" in the LO selection button, or attach a Gnd symbol (far left in the "Basic" tab) to the negative lead from the battery and select "Gnd" for the "LO" option.

And start with R1 at 150 Ohms. Its value sets the upper limit of current that can flow in the circuit. Too little current and the zener cannot function. Click on the "I" button of the meter with R1 at 10k Ohms and watch what the current drops to ( < 2 mA) - WAY below the amount of current needed to get the zener to control the voltage ( > 47 mA). With R1 at 150 Ohms, The I value measured at VF1 is 50.02 mA - and the zener is working.

 

[Muttley600]

ok, readings now:

2k = 837.19mV
5ohm = 6.3V
10k = 177.34mV

changing R1 to 10k I now have A reading of 631.65uA

150ohm = 41.99mA with 5ohm at R2

doh, just realised that R1 is the main resistor, meaning I've done it all wrong **broken link removed** so are you saying R2 is the load one, shall I move voltage pin

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Now getting 2.53mA, am I messing things up

 

[cowboybob]

Keep in mind that a zener is not meant to control "gross "load" changes. Its control window is fairly narrow.

Leave R1 at 150 Ohms and vary the "load" resistor while observing the voltage (and current) - it'll hover around 5 VDC ( 5.1 being the center voltage it's designed for) and the current will vary.

As you increase the load (by decreasing the "load" resistor's value) the zener will begin to loss control and VF1 will drop below 5VDC. THEN you can decrease R1 (allowing more current to enter the system) and VF1 will come back up to its spec'ed holding voltage. It can be a subtle process.

What a zener can tolerate (within limits) is fairly "gross" Vin variations. Change the battery output up and down to demonstrate.

 

[Muttley600]

ok, screen as I have it now, varying load

5ohm = 77.42mA - 387.1mV
2k = 2.53mA - 5.06V
10k = 507.62uA -5.08V

why do I get the feeling this is meant to be load at 150
how can you have current without voltage potential

nuts, ignore me, I'll correct readings, still had V on gnd **broken link removed**

ok, tried going down, suprising how low it will go holding 5V, once down to 400ohms, it just dropped under 5V, down to 100ohms it is 4.42, now to decrease R1, hope I'm getting there **broken link removed** don't give up on me

80ohms on R1 brings it back to 5.01V

changing battery to 6V, R1 back to 150ohms, lets see, hope your enjoying this, I am **broken link removed**

now at this rate I'm going to be able to run a hotel off this little battery, I can't get it back up to 5V **broken link removed** shall I up R1

ignore that last remark, 5ohms & 800k load, it's back **broken link removed**

so the lower the battery voltage, you use a lesser resistor to get zener to hold 5V, so if you had a larger battery, you would use a larger resistor to get it to hold 5V, the bigger the resistor the more heat you have right **broken link removed**

How's my understanding coming along

 

[cowboybob]

I may not have made this clear at the onset:

the point of the whole circuit is to provide a steady output voltage to the load (R2) by controlling a fairly severely varying input voltage.

R1 is the current limiting element of the zener circuit.. "Load" (or R2) is the resistance of the device (were we to have one) that the zener is controlling the voltage supply for.

Get the screen showing what you have at the moment (with the multimeter in place) and attach it to the next post for me.