Led display Digital Voltmeter question

[Guest]

does anybody have a veraboard/stripboard/breadboard layout of this voltmeter?

Kane

 

[MP1]

If you download the Eagle layout files, you can move the parts on the board. Breadboards, Veroboards, etc. are boards with multiple holes on a 0.1" pattern. You could edit the board layout by removing the traces, then moving all the parts so that they match the 0.1" pattern. ..or you can delete the board layout and automatically generate a new board layout from the schematic, then place all the parts where you want them. After that, using the autorouter will put the line where you can see them and know where to put your wires on the breadboard.

MP

 

[mixos1]

I came across a Digital Thermometer that used ICL7107 and it had a subcircuit to easilly produce the -5V that ICL7107 needs. I post it here:

 

[stuee]

Is there any wat to get this circuit to measure amps aswell or just amps?
pref 20-40a

 

[ante1]

stuee,

Yes, this circuit can measure current if you like. You need a shunt for this.

Ante :

 

[ante1]

This will help I hope!

http://www1.jaycar.com.au/images_uploaded/shuntmul.pdf

Ante :

 

[ante1]

Stu,

Continuing from message: I have drawn a circuit for you that show the basic connection for your equipment with the meter hocked on. With the switch you choose current or voltage reading. Current is measured over the shunt (resistor voltage drop) and the voltage across the terminals pos and neg.

Ante :

View attachment 35354

 

[XJNick]

Hi,

I built this voltmeter circuit, but have a question regarding the power supply for it. I notice the schematics show ground symbols in addition to + and - supply voltage. So would these indicate true earth grounds? I ask because I want to be able to use a digital voltmeter like this in my car, where (I believe) there would be no true ground?

Is there any way to get around this? I was able to get the 7805 to produce 5.0 volts when it's ground leg is attached to the - terminal of the 12 volt battery i'm using (and its V. in leg attached to the +12 volt battery terminal). I doubt this would work for the 7905 to make a -5volt supply though? ???

Thanks
-Nick

 

[MP1]

You will need a negative voltage. A 7905 will only work with a negative input. There is a chip from maxim that will do what you want. It just converts your +5 to -5. Another way to do this is to use an inverter circuit to divide your battery voltage by two and give you a bipolar 6 volt supply. The maxim chip is the best solution.
There are some additional notes earlier in this thread regarding the -5 volt. It is here:
http://www.electronics-lab.com/forum/index.php?board=2;action=display;threadid=119;start=15

There were also some corrections to the circuit posted in earlier messages and also here:
http://www.electronics-lab.com/forum/index.php?board=4;action=display;threadid=353


MP

 

[audioguru2]

Nick,
Ante's circuit in his reply #37 above, is a cheap and simple way to get -5V.

 

[Xenobius1]

Hi all,
Where can I get the "EXACT" PCB pattern layout for this project? I tried to used the layout in this post but everytime I print it out it's always oversized..
I set my printer to 1:1 but to no avail..
please help.. :'(

Try to use a drawing software like photo shop or paint shop pro to resize the pcb and before you print always check the size from print preview so you would know if it's over sized or not!

 

[Gusk4x4]

Hi all,
Where can I get the "EXACT" PCB pattern layout for this project? I tried to used the layout in this post but everytime I print it out it's always oversized..
I set my printer to 1:1 but to no avail..

It is written in the article that you must set your printing software to resize the layout to 35% of the original size, or use the dimensions in milimeters that are under the picture on the article.

It works perfectly.

Regards

 

[Gonzakpo]

Hello...
Before starting to do this circuit There´s something i must know!!

I want to place this circuit in a power suply which goes from 0 to 20V
......and i was wondering if it this circuit displays the voltage with two decimals or only one.....(when you are using the R3 for measure from 0 to 20 v obviously)......
I hope it uses two decimals because if not I will have to find anotehr circuit....
I imagine you already notice that my english is terrible....that's because 0m from Argentina.....so.....sorry for my english...

Thanks....Chau!!..Saludos desde Argentina

 

[Gusk4x4]

Hello...
Before starting to do this circuit There´s something i must know!!

I want to place this circuit in a power suply which goes from 0 to 20V
......and i was wondering if it this circuit displays the voltage with two decimals or only one.....(when you are using the R3 for measure from 0 to 20 v obviously)......
I hope it uses two decimals because if not I will have to find anotehr circuit....
I imagine you already notice that my english is terrible....that's because 0m from Argentina.....so.....sorry for my english...

Thanks....Chau!!..Saludos desde Argentina

Hello, i´m from Brazil.

When measuring from 0-20V, this circuit displays 2 decimals.

Regards

 

[Gonzakpo]

Ok thanks.........I won't say anything about the footbal match..

Chauuu

 

[Gonzakpo]

Hi......I'm here again........with more doubts :-\
First of all i would very happy if another person corrovorates if this circuit displays two decimal when measurin from 0 to 20.

And my other question is: Which R1 should i use!!!?? 180K or 100K (in the datasheet and in the eagle circuit says 100k but I'm not sure what to do!!!)

Is there another correction in the values of the resistors or the capacitors???

Thank you very much.......I will be waiting for your answer (I want opinions!!!)

 

[Gonzakpo]

Sorry....i forgot to say something........in the pcb all the pin 5 of the MAN6760 (which is the pin of the dot in the display) are send to ground!!!.........IN THAT CORRECT!!!??? (i don't think so)...

OK that's all.....thanks again........

 

[wired1]

In browsing this forum, I believe I have seen corrections posted for this circuit. Some were in the "General" area. I do not recall where but there were two different places that it was discussed. Perhaps a search could help you.

 

[metal1]

Hello

I just wantes to know what is the purpose of REF HI and REF LO pins, also does the above schematic has a 2.000 volt full scale or not .

In AN023 application note, it is said that to obtain 2.000 volt full scale, pin 29 cap must be 47nF, pin 28 resistor must be 470 K, and pin 27 cap must be 220nF. Is that right. I noticed that you done the opposite.

Thanks

 

[maestrodamuz1]

I have done enuff research to confirm that it works the way it is in the schematic. I have carried it out and the DVM worked to an accuracy of 98%. Don't worry it will work.