TTL homebrew CPUs

[dwight elvey]

>From: "Chuck Guzis" <cclist at sydex.com>
>
>On 10 Jul 2007 at 11:25, der Mouse wrote:
>
> > But you get only tiny on times.  Add another resistor and use a larger 
>cap
> > and you can stretch the on time - indeed, with a bit of care you should 
>be
> > able to get pretty much any duty cycle and frequency.
>
>Well, any frequency limited by the ionization time of the gas at any
>rate.  IIRC, that's something like 20KHz.
>
>If you want to use a neon bulb (or a gas triode) as a sawtooth
>oscillator (one of the more useful aspects of a relaxation
>oscillator), you can improve the linearity of the charge ramp by
>using a very high 500vdc or more) supply voltage and a large series
>resistor.
>
You could also put a current source instead of a resistor.
This can be made with either a transistor and s few resistors
and diode or a jfet.
Dwight

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