[sdiy] freq generator and lab power supply

[Bert Schiettecatte]

hi all,

during all this DIY-ing I realized I still don't have a
decent symmetric power supply for my breadbording experiments. I'm using
this little DC wall wart that outputs +6, +9, +12 etc. Can anyone
recommend an affordable power supply with voltages like
+3,-3,+5,-5,+12,-12,+15,-15 etc?
a DIY power supply might also be an option ...

the same for a function generator: I've been trying to debug this bandpass
filter
from 'the art of electronics', page 277. I only have an oscilloscope, and I
have a
555 set to a certain frequency. I'd like to have a function generator at
this point
to find out why my filter doesn't work...

thanks
bert