Often with projects that uses Logic devices such as previous projects like the devils drone sequencer or the Sound Activated Dancing LEDs you need to create a clock signal to make the logic transition from one state to the other. you don't want to have to deal with the clock (or oscillator) part of the circuit in the experimentation stage so you need something that is capable of creating a clock signal. This is just that piece of test gear.
it also uses the same power supply you're using to power the Logic ICs in question.
here is an example of a commercial version http://uk.rs-online.com/web/p/needle-point-probes/5375163/?origin=PSF_437277|alt
aswell as the layout and schematic - I have included some oscilloscope pictures of what it actually does.
Sorry if my explanation is a little off today in the making sense department - I am suffering from cluster migraines and one of the symptoms is Aphasia. the important thing is that the actual layout and circuit are correct - which as you can see - is the case!
 |
| As you can see I have soldered a nail to the pulse output - I've found this is the ideal probe |