TTL homebrew CPUs

The one I was thinking of -- the neon bulb blinker -- is this circuit R o----------/\/\/------------+--------------+ | | | --- --- O --- C Neon Bulb | O (e.g. NE2) | --- | | o---------------------------+--------------+ The circuit depends on the fact that a neon requrires a higher voltage to strike than appears avross it once it's struck. R is chosen so that a glow discharge cannot be maintained in the neon with the current available from the supply through R alone. Waht happens is that C charges from the supply through R. When the voltage across C reaches the striking voltage of the neon, the latter strikes and discharges C until the votlage across the neon is less than the maintaining voltage. At this point the neon goes out, C starts to charge up again. This was probably the first circuit I ever built, before I went to school. I know it was before I'd learnt to solder, I built it using those 'chocolate block' terminal strips. I thin R was 1M, C was about 0.1uF. The DC supply was a 90V dry battery. -tony