What to do with big capacitors?

[Richard Wallace]

0.025 Farad x 40 Volt = 1 Coulomb electrical charge.

That's one Ampere flowing for one second, or 10 mA for 100 seconds, assuming a load circuit that will draw a constant current. So yeah, that capacitor can power a small logic circuit, through an appropriately designed regulator, for at least a minute or so.

More realistically, a load circuit equivalent to a constant 2000 Ohm resistance (the path from your left index finger to your right index finger, through your body, under some conditions) would initially draw 20 milliAmperes, and this would decay exponentially with a 50 second time constant [ i(t) = 0.02 x exp(-t/50) where t = time in seconds and i(t) is current in Amperes ] so that after 2.5 minutes the current will be less than 1 mA and the voltage less that 0.5 Volt.

20 mA is not enough current to send your heart into ventricular fibrillation, but enough to get your attention. Look here for more on electric shock.