Simple circuit to generate 12VDC from a 9v battery?

Hello everyone,
I need to generate 12vdc from a 9v square battery, cheaply and simply,
supplying about 20mA.
I have looked at DC-DC convertors, but haven't come across anything
suitable.

I found this circuit that does something similar with a 555 timer but
it can only supply about 12mA. Any ideas how to increase the current
capability a little?

http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm#5volts.gif

Any other simple circuit ideas welcome
Thanks
Marius

.

Relevant Pages