seek help in drawing a schematic diagram from the Breadboard

[Subi]

I have a small electronic circuit. Attached pictures are all of the same circuit.
1) can anyone draw a schematic diagram from these pics?

2) I have the electrical input/output and component details of the circuit. I want to modify the circuit also if I find someone to help me.

Unfortunately I can't upload the pictures here, getting errors. If anyone give me his email address I can send the pics. My email is <SNIP>

Moderetors note : removed email to avoid spam

 

[Nanren888]

Usually works fine for smaller images. Try shrinking it?
I think there are still some free schematic capture programs out there, or at least free versions of bigger ones.

 

[bertus]

Hello,

Pictures upto 300 kB are no problem.
Almost any paint like program can be used to resize the pictures.

Bertus

 

[Subi]

Usually works fine for smaller images. Try shrinking it?
I think there are still some free schematic capture programs out there, or at least free versions of bigger ones.

Thanks

Hello,

Pictures upto 300 kB are no problem.
Almost any paint like program can be used to resize the pictures.

Bertus

Thanks Bertus..I'm gonna try uploading again after shrinking the images

 

[Minder]

If you want a schematic capture pgm in the future, Kicad is a very popular one with lots of tutorials and a forum.
M.

 

[Subi]

hi, please see the uploaded file for help. Please let me know if any extra information is needed

 

[Subi]

Usually works fine for smaller images. Try shrinking it?
I think there are still some free schematic capture programs out there, or at least free versions of bigger ones.

Hi please see the uploaded files

 

[Subi]

If you want a schematic capture pgm in the future, Kicad is a very popular one with lots of tutorials and a forum.
M.

Thanks. Please see the uploaded files if you can help

 

[Harald Kapp]

can anyone draw a schematic diagram from these pics?

You can. Take the first of your images. replace the boxes representing transistors by the standard symbols.
Draw only the existing connections (do not draw traces that are interrupted (marked x in your image).
Then arrange the symbols and wires such that a good looking schematic evolves.

Hints:

1. draw the positive supply as horizontal line on top of your schematic, negative supply at the bottom (just a convention). In your image '-' is at the top and '+' at the bottom. Not wrong but just not conventional.
2. D1, D2, D3 and D4 form a diode bridge which can also be drawn in a kind of standard fashion.

 

[73's de Edd]

Sir Subi . . . . . .

BEFORE . . . .my making a schematic . . . .

Is that a functioning board and what is its purpose. ( A solid state version of a current loop supply for a teletype ? )
Since the currently drawn out connections do not seem to make a viable working circuit.
I have initially simplified the drawing somewhat, by dropping the clutter of unused lines that do not terminate into circuitry components, plus numerous "U" wire crossover symbols.

As the circuit layout is now being drawn . . . it is deviating from the norm, with its power input on the right side and the output at the left .
Also, the DC positive voltage is at the bottom versus the top .
UNLESS your concept is biased by a native language that is normally read from bottom to top or from right to left.

I see the 100k pot wired in order, with it using R1 and R2 on either end to establish its effective range with its center wiper feeding its variable output setting to the base of the small signal NPN transisistor.

I see the incoming 76 VAC coming into a Full Wave Bridge configured with D1-2-3-4 and a (1000) pf mylar noise / spike filter shunting them and then a 220ufd @160Vdc E-cap storing up the raw rectified DC supply.

LOOKING FOR THE LOGICAL B+ POWER FLOW PATH . . . . .

I now seem to see the sole viable flow path being from the MAIN B+ coming in at the bottom #1 line from the joined cathodes of D1 and D3, with filtering supplied by " BIG cap C".
The first feed off is being to R2 . . .47k . . . and it then going to the collector of small signal NPN transistor 2SC1815.
So with a 100VDC B+ hitting it,that transistor will then be able to see no worse than 2.25 ma of current with a potential .225 watt of total dissipation.
Whoa . . . .horsie . . . . . . that potential voltage level would exceed the collectors 60V spec below.

ABSOLUTE MAXIMUM RATINGS at Ta=25℃ Collector-Base Voltage Vcbo 60 V Collector-Emitter Voltage

Then the B+ feeds up to R3 . . .560k . . . to the max cw lug of the 100k pot . . . .while its other max CCW lug goes to R1 . . .6.8k . . . and then to ground. No problem is seen there as they are just seleccting out a specific range of adjustment capability .
Then things get wierd, with the B+ then going into the anode of a GREEN LED and exiting out its cathode to go up to the " b " terminal of your O/P connection.
It would then have to pass out thru that " b " terminal and come back to enter as your "a" terminal, which then goes direct to the collector of your 2SC2233 "power" transistor, since it is capable of 40 watts when heat sinked.
BUT that transistor also has a 60V collector spec.

Sooooooooo . . . confirm the units raw DC supply voltage, seems like it should be ~ 100 VDC with using a 76 VAC supply input.

That incoming voltage then goes solely to the 2SC2233 collector, and if its base was being FULLY driven on by the small signal transistor the power would flow out the 2233 emitter to the R4 resistor . . 120 ohm . . . to complete a ground connection.

But all hell would break loose, as 100V at ~ 833 ma would vaporize your earlier series LED with its 20-30 ma rating and your R4 resistor to ground, unless it was a 100 watt unit.
So looks like there must be an error in interpreting the strip board connections wiring.
Seems like I . . . DO ! . . . do see two component side wiring U jumpers being installed near the transistors, and also a yellow wire jumper.( or component lead wire extender ? )
Are they being accounted for in your wiring ?.

Now if this unit is supposed to be a supply andwith its output being at the a and b terminals, the top a connection would go to the emitter of the power transistor and the transistor collector would also be receiving appreciable + supply voltage.
The b connection would be going to ground / negative, and not thru the LED as it is now, in its path to ground..

If the LED is only being a power indicator, it would be wired between ground (cathode) and have a series current limiting resistor from the LEDS anode to the a output connector. ( But the LED brightness would vary with different settings . )

If the smaller transistor was intended to be making a Darlington interface into the power one, there would be an interconnection between the two collectors.

REFERENCING TO THE MARK down BELOW . . . . .

The YELLOW is questioning the output connections.
The PINK is questioning only a sole connection being made to the collector.
The GREEN is questioning the wattage of the R4.
The ORANGE is questioning the collector solely going over to the A output . . . . . or if you have reversed the collector and emitter.

Did I make any error in my chopping out of dead end portions and line crossovers ?

REFERENCE . . . . .



73's de Edd ....


Appearances are not everything; it just looks like they are.




.

 

[Minder]

Here is a few symbols to indicate Power and Common etc.
M.

 

[73's de Edd]

Sir Subi . . . . . .

Where you g o o o o o o o o o o o o o ?

This initial schematic, as is being interpreted from your drawings info, should give you a basis to recheck its connections for their correctness.
It is having the left half of the schematic being spot on to your findings, completely up to the Base connection of the 2SC1815 NPN, small signal transistor.
From that point, further on to the right, it is then dependent on your possibly having made a misread of the Collector and Emitter connections of the 2SC2233 transistor.

Use its info in your circuit connection tracing to confirm if the resistors, their values, or even existance and connections are being as is shown.
Then there is being the questioning of the LED wiring install and the presence and value of the shown Rz resistor.
The designated Ry resistor would be a load resistor .
If the multiplied gain product of using the transisitors as a direct coupled Darlington pair should be a excessive of more than required, the value and presence of Rx resistor could be used to decrease their overall gain product.

PRELIMINARY DERIVED CIRCUIT SCHEMATIC . . . . .



73's de Edd .....


Roses are red violets are blue . . . . . I'm schizophrenic . . . . . and so am I.




.

 

[Subi]

Sir Subi . . . . . .

Where you g o o o o o o o o o o o o o ?

This initial schematic, as is being interpreted from your drawings info, should give you a basis to recheck its connections for their correctness.
It is having the left half of the schematic being spot on to your findings, completely up to the Base connection of the 2SC1815 NPN, small signal transistor.
From that point, further on to the right, it is then dependent on your possibly having made a misread of the Collector and Emitter connections of the 2SC2233 transistor.

Use its info in your circuit connection tracing to confirm if the resistors, their values, or even existance and connections are being as is shown.
Then there is being the questioning of the LED wiring install and the presence and value of the shown Rz resistor.
The designated Ry resistor would be a load resistor .
If the multiplied gain product of using the transisitors as a direct coupled Darlington pair should be a excessive of more than required, the value and presence of Rx resistor could be used to decrease their overall gain product.

PRELIMINARY DERIVED CIRCUIT SCHEMATIC . . . . .

View attachment 48960

73's de Edd .....


Roses are red violets are blue . . . . . I'm schizophrenic . . . . . and so am I.




.

Hi Edd,

Thanks for working on the circuit. This is a functional ckt as I am using it currently . Essentially the circuit is to get variable current of 0 to 25 ma (milli amperes) across the output load. The current is varied by the use of a POT. The output load for testing purpose is a 6.8k resistor. Maximum voltage across the load is 85 Volt.

The following are the readings I took on the functional circuit .

1) Input is 72 VAC that's fed across the input which goes through a bridge rectifier and other components as on the diagram.
2) Open terminal voltage (without load 6.8k) across the output terminal is 96 V dc.
3) using testing load resistor 6.8k and progressively measuring the outputs while varying the POT slowly clockwise , the readings are ( 0 vdc/0 ma, 66.1 vdc/16.8 ma, 72.1 vdc/18.9 ma, 70 vdc/18.8 ma, 68.5 vdc/ 18.9 ma, 67.9vdc/19.2ma, 67.3vdc/19.3ma, 65 vdc/19.5ma, 72.4vdc/23ma, 71.2 vdc/22.9 ma full clockwise POT position)

Note:
* the ckt board has only 4 resistors R1, R2, R3 and R4. There's no Rx, Ry or Rz on the actual circuit.
* Can you build a ckt on the bread board as per the picture of the circuit board to get the maxm output current of 23 to 25 ma across the equivalent test load of 6.8k?

 

[Subi]

OK.., RZ is the load 6.8k resistor. but there's no Rx or Ry on the actual ckt

 

[ratstar]

Love the work 73's de Edd!!