What is "ground"?

[williamchia]

Hi all,

Sorry but i am still not sure what is it?

I am doing a circuit to flash 2 LEDs, and i use only one 9V battery. "+" of the battery is possitive and "-" is negative (obviously...), then what is gound? Does the "negative" means ground in this case?

The circuit is attached (taken from: **broken link removed**)

I use 7805 to control the output to be +5V.

Initially i connected pin 12 and 31 to negative, but the LEDs do not light up. When i disconnect them from the negative, the LEDs light up but do not flash (they should).

Where should i connect the pin12 and 31 to? Ground? But what is "gound"?

Thank you very much! Any comments or helps are appreciated!

Regards,
William

 

[pravardhan]

Yes, Ground means -ve for a single power supplyand is different for dual power supply. what u will be using is a single power supply.

Ok, first of all in IC7805, connect the pin2 to -ve and unregulated +ve voltage to pin1 and pin3 is the regulated +5v supply. (pl. refer the data sheet of 7805)

And what you are using is a microcontroller & it has to be programmed/burned using a computer and an programmer hardware connected to the PC.

You can use a 555IC to flash 2 LEDs alternately and why go for microcontroller.

 

[williamchia]

Hi pravardhan,

My final goal is to use the microcontroller to do analog digital conversion and send the data to pc. I am just testing it on simple project first..and it is so sad that...i couldnt even make the two LEDs flash...

I have used the microcontroller programmer and transfer the hex file given from the website to my microcontroller.

Theoritically, only LED at pin 38 and 37 will flash, but now the case is they dont flash but just light up when i disconnect the wire at pin 12 and 31 from the negative.

I have checked the circuit and everything..they seem all right..



Regards,
William

 

[pravardhan]

Better thing is use PIC16F84A and its very easy and you will many projects and circuits for this microcontroller.

Do you get any error during programming the microcontroller?????
Or search any other site for some programs and i don't believe the programs given in the site u mentioned.

 

[williamchia]

It works now!!

Thanks!

The problem is..well...on the battery...(After struggling for 3 days trying to find out what went wrong)

Anyways, thanks a lots,pravardhan.

Regards,
William

 

[pravardhan]

Electronics means like that only.

For a safer side buy an adapter ranging from 1.5Volts to 12volts and it is more economical.

 

[williamchia]

Actually i am not quite sure. the battery was working because when i tested with multimeter, there was in fact 5V running in the circuit.

I dunno, it just work when i change another battery...

 

[pravardhan]

Were you using an 9V battery?? I think the circuit depends on Current also and not only on the Voltage. I recommend not to use a 9Volt battery.

 

[williamchia]

yea, 9V battery. What do you recommand for power supply?

I am using battery because they are cheap and other power supply seems will cost a lots.

ok, now i am trying the program that i wrote for the microcontroller
*PRAY*...

 

[pravardhan]

An adapter or eliminator is best. Or you can use 4 AA sized battery to get 6volts. Or if you want to use a 9v battery, then buy an Alkaline battery like Energizer or Duracell.

 

[Kashi]

Ground is a reference point of your circuit from where u can start analyzing ur circuit.