[Led display Digital Voltmeter question]

Dear Lupe,

Can you elaborate,why the refrence was not proper using 9 V battery?

I want to use this voltmeter as car dashboard meter, In such case the battery voltage will be coverted to +5 V using a 7805 regulator and -5V using IC7660. Hence the ground of the power supply and voltage to be measured will be same As per the circuit given on www.electronics123.com if I connect the IN LO (pin30), IN HI (pin 31) and COM ( pin 32) of IC7107 to ground these pins also be at battery ground. Would this configuration work?

[Led display Digital Voltmeter question]

You may go through the following web link this will help you to select the correct resistor :
http://www.kitsrus.com/pdf/k61.pdf

if you have finished the project, can you share your experience, I want to construct this as a dashboard meter for my car.

[Led display Digital Voltmeter question]

Would you pls suggest the capacitor and resistor types for the project?

Thanks

[Led display Digital Voltmeter question]

One may be last question before I start construction: the capacitors in the circuit have to be ceramic or other types may also be used.

[Led display Digital Voltmeter question]

Thanks for clarification, can you suggest what capacitor value to be used to supress the alternator noise?

Since I shall be meauring battery voltage can I eliminate the -ve voltage and leave the IC7107 pin unconnected? I will put a diode in the supply line to avoid wrong polarity apllied to IC. Will it work?

VK

[Led display Digital Voltmeter question]

Thanks for reply, I have decided to use IC555 to generate -5V as it is cheap and easily available, In such case should I take +5 V from  output  of    7805    to  make  -5V OR it is better to generate -12V with IC555 and then regualte it to -5 V  using 7905?

Will -ve terminal of battery be the ground point in the circuit?

[Led display Digital Voltmeter question]

I have gone through all the 19 pages on board but still some questions remained to be answered:
I want to use this VM to measure car battery voltage, what should be the ground point in this case? This has been asked earlier also but no replies.

If I use the car battery (12V) as input to 7805 and 7905 to genrate +5 V and -5V to power the IC will it work ? Will the

[LED Display Digital voltmeter]

I want to construct this voltmeter as a car dashboard