Help: 9 volt batteries

[kunene]

1. I would like to power a a TL072 opamp which is a rail to rail (+15/-15 volts)
2. I don't know about the current output/input
3. I'm using the TL072 for a wein-bridge oscillator as shown in the attachment.

Question: How to get the +15 and -15 volts from the 9 volt batteries (plural)?

 

[crutschow]

You can't unless you use switching regulators to change the voltage.

But the circuit should work fine with two 9V batteries in series, one for the plus voltage and one for the minus voltage. The junction of the two batteries in series goes to circuit common. The maximum output voltage will be reduced, of course, but otherwise there should be little difference in the circuit's operation.

 

[kunene]

How about I use two 9 volt batteries in series so that I get 18 volts, then use 15 volt regulator to get 15 volt?

 

[alec_t]

You could do that; but then you'd need another 2 batteries and a 15V -ve regulator as well to get -15V.
Why not just use +9/-9V as suggested in post #2?

 

[kunene]

You could do that; but then you'd need another 2 batteries and a 15V -ve regulator as well to get -15V.
Why not just use +9/-9V as suggested in post #2?

But the rail to rail voltage of TL072 is +15/-15 volts. won't that that make the circuit not to work?

 

[JimB]

the TL072 has a MAXIMUM supply voltage of +/-18volts.

The characteristics in the data sheet are measured at +/-15volts.

The TL072 will work quite happily at +/-9volts if your signals are less than +/-9volts.

If you want to work with signals up to +/-15v then you need a +/-15v supply.

JimB

 

[kunene]

the TL072 has a MAXIMUM supply voltage of +/-18volts.

The characteristics in the data sheet are measured at +/-15volts.

The TL072 will work quite happily at +/-9volts if your signals are less than +/-9volts.

If you want to work with signals up to +/-15v then you need a +/-15v supply.

JimB

what signal you referring? coz its an oscillator, it generates a sinusoidal wave without any input.

 

[JimB]

what signal you referring?

Just a generalisation.

JimB

 

[alec_t]

The Wien oscillator will work well with just +9V/-9V supplies.

 

[kunene]

thanks all.