How do I create a reproducible spark using 120 volts?

Question

How do I create a reproducible spark using 120 volts?

Answer 1

You do not indicate what type of spark you need or how it must be triggered.

In general, an effective way to get a repeatable spark is to:

1. Step up then rectify your source.  

2. Use that to charge a capacitor (which will store a known amount of energy)

3. Disconnect the capacitor from the source

4. Switch the capacitor with a MOSFET across a spark gap.