194 Transistor Clock Will Blow Your Mind

It’s nice to have tip put on our desks that we think everyone, yes everyone can enjoy. The Transistor Clock is just as its name implies, A clock that doesn’t rely on ICs. 194 Transistors, 400 resistors, 566 diodes, and 87 capacitors are all that makes this clock tick – no programing, and most importantly no Arduino. The clock is offered as a kit, but there is a complete parts list and manual (including debugging help) so anyone can build (and fix) their own. The Transistor Clock might even beat out the VFD Clock and the Word Clock on the ‘pure awesome’ scale, tell us your favorite in the comments.

[Thanks Hoopstar]

59 thoughts on “194 Transistor Clock Will Blow Your Mind

  1. Cool but now redesign with 87 dual 12ax7 triodes, 4 rectifiers 5U4 and six nixie tubes. Would fit nicely in a 6′ rack and consume several 100 watts. Little treaking of components and you have an ENIAC style clock the ultimate pre-silicon clock. Would cost over $1000 in parts. Fun project. any body up for the challenge.

  2. The discrete transistor approach is cool, but something about the layout just doesn’t do it for me… I’d consider more geometric logic blocks so you could more easily follow the functionality, along with some blinky leds that display logic states of the counter or something.

    I’d also take second Eric’s comment about using Numitrons to add a bit more flair to it (note Numitrons do not require a high voltage power supply, they would be a drop-in replacement for the 7 segment displays).

  3. @Peter
    Nope, no IC’s at all. (and you *can* build a regulator without IC’s you know)

    Faultfinding should be a total doddle, but it’s finding that you somehow inserted half the diodes backwards that really hurts.

    I gotta say, I couldn’t imagine a better introduction to basic electronics than constructing this; learning to solder, understanding several basic circuit concepts, and debugging problems should be easy and similarly instructive. Serious Win.

    I was wondering why it seemed to have so many transistors, so I browsed the block diagramme and circuits. The counter decoding, for example, is in two layers, binary to decimal, then decimal to 7-segment.

    This is very like the way you would build a clock using RTL, DTL, TTL or CMOS, but not the way you would go if you weren’t trying to imitate IC’s.

    It would seem more direct to diode-decode the 7-segment drive by directly decoding the binary count. Similarly considerable economy could be had by using synchronised oscillators rather than bi-stables in the prescaler.

    At some point the number of components in individual decoders becomes greater than multiplexing a single decoder, and a straight binary counter becomes more component economical than individual digit counters.

    Unlike IC counters these RDTL bi-stables provide both Q and /Q outputs, allowing complexity to be moved into a decoding tree of diode AND gates, and in low speed state-logic like this they can be just about as as wide as you like.

    As it stands an alarm function could be as simple as some thumbwheel switches and a few more bits.

    I really like the idea of putting in LED’s all over the place to show off the internal workings, and/or using LED’s instead of boring diodes for steering and decoding…

    A neat showpeice and demonstrator, but perhaps not the optimum way to do it with transistors.

    Love all the clocks guys – real flashes of inventiveness.

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