hai all,

currently im using LM324 to make simple amplifier and i have 12V to put at Vcc+. Now i have problem to supply Vcc- because i did not have negative voltage source. Here i need some help how could i supply Vcc- with only 12V source????

 

http://www.societyofrobots.com/electronics_negative_voltages.shtml

You need to generate it.

Read the link, it will tell you about how to get dual supply from a single supply using a maxim IC and the two battery method.

 

The LM324 is supposed to be able to operate off a single power supply 3-32V range. The input common mode includes ground.

If you actually require a split supply (centre-grounded) you can employ a resistive voltage divider - with equal resistors to create a virtual ground at the centre point. Some capacitive bypassing to both + & - rails might be beneficial.

You can be a bit more "tricky" and use one of four the on-board amps with the equal R voltage divider as a unity gain (buffer) ground driver.