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A project log for SPDT16: 16-bits arithmetic unit with relays

Let's imagine I could get about 200 SPDT relays. Of course I would know what to do with them :-D But will 200 be enough ?

Yann Guidon / YGDES 05/04/2016 at 08:320 Comments

Realising that many relays are in parallel and amounted to DPDT, I have chosen to wire the coils in series, with one lamp instead of two per pair.

@jaromir.sukuba is not happy about the "savings", feeling that this reduce the Blinkenlichtheit of the circuit, but I actually added some missing lights for Cin for example.

I'm not happy with the many resistors for the lamps when they are not in series, they would drop each about 3V at 50mA, 150mW each... I might add another power rail (sinking, not sourcing) to reduce the losses. That would be at 2.5V and a diode must replace the resistor so it doesn't turn on when the level is 0V.

The CLK, MUL and DIV signals are shown as before but in reality, the relays are paired in series with adjacent bits, with only one lamp.

I have already an idea of the look with the colored lamps inbetween the round relays that form alveolas...