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Triggering Germanium

A project log for Clockwork germanium

A retro version of Yet Another (Discrete) Clock, with vintage parts

SHAOSSHAOS 04/10/2016 at 03:1113 Comments

So going further with replicating circuits from old Russian magazine (1983):

Now using 2 NANDs (version with LEDs) I built trigger (as on Fig.7 above):

Then added couple resistors and couple capacitors to get universal trigger (as on Fig.8)

That can toggle state if inputs 5 and 6 connected together - 100 Hz:

1 kHz:

5 kHz:

It looks like this is a limit (and trick with "speed-up" capacitor doesn't help) - probably I should play with values of resistors and capacitors...


UPDATE: Everything above was for C1=C2=10000 pF, now I'm trying 470 pF

10 kHz:

20 kHz:

On 50 kHz it doesn't look good...


UPDATE (04/10/2016): Today 50 kHz looks much healthier - I don't know why :)

But if go higher output shape is quickly shifted up (to the ground) - probably because of natural limit that caused by latency about 5 us...

P.S. Almost forgot - 32 kHz sine signal :)

P.P.S. Redrawn schematics:

Note: Wires that goes above diodes are NOT connected to diodes' cathodes as may mistakenly appear in your mind (check closely - there are no dots there)

Discussions

Yann Guidon / YGDES wrote 04/11/2016 at 05:03 point

Thanks for the drawing :-) BTW you should also have a reset input, but that's just one more diode.

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Yann Guidon / YGDES wrote 04/11/2016 at 03:35 point

Nice touch with the 32KHz signal :-)

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jaromir.sukuba wrote 04/10/2016 at 15:35 point

I assume for a few first stages of binary divider we need to use faster transistors - the same as in oscillator. let's spare the lazy MPxx for later stages. we will need a lots of them

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Yann Guidon / YGDES wrote 04/10/2016 at 15:38 point

That's exactly my idea :-) That's why I'm stocking less lazy parts too.

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Yann Guidon / YGDES wrote 04/10/2016 at 04:03 point

What's the value of the resistors and capacitors ? Can you redraw the whole diagram ? Arent's some diodes superfluous ? I should try the DCTL version as used in the CDC6600...

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SHAOS wrote 04/10/2016 at 04:07 point

All resistors are 10K as on the picture 8. For capacitors instead of 3300 pF I took what I had on hands - 10000 (marked 103)

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Yann Guidon / YGDES wrote 04/10/2016 at 04:17 point

Faster gates use lower resistor values, AFAIK, so this might explain some speed limits... Can you try with 1K and see how much faster it runs ?

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SHAOS wrote 04/10/2016 at 06:14 point

I tried 470 pF - works up to 20 kHz

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Yann Guidon / YGDES wrote 04/10/2016 at 06:32 point

Hey it is "almost there" :-) Could you try with a sinewave input ? That's what the 18KHz generator will provide...

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Yann Guidon / YGDES wrote 04/10/2016 at 16:09 point

Well, I realised something: trace shapes are an esthetical thing, since Ge commutes at about 0.2V so as long as the circuit reaches even 1V it's ok. Now I wonder how your diodes influence this...

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SHAOS wrote 04/11/2016 at 03:29 point

I'm not sure what do you mean exactly :)

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Yann Guidon / YGDES wrote 04/11/2016 at 03:34 point

Well... I'll experiment :-)

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Yann Guidon / YGDES wrote 04/10/2016 at 03:27 point

It's starting to work ! I'll have to analyse the schematic and try with other kinds of transistors...

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