This computer is based on 24V 4PDT relays (Four-Pole-Double-Throw). Each of the relays has a LED indicating whether it on or off.
Power supply has 6.5A/24V output. 24V was selected instead of widely available 12V to reduce the current and make wires thinner. But this decision has an opposite side: there are no LEDs with integrated resistors for 24V.
ALU
Relays required for ALU components:
| Component | Number of relays |
|---|---|
| Adder | 16 |
| Subtractor | 16 |
| Logic | 16 |
| Shifter | 0 |
| Result register | 13 |
| Decoder | 5 |
| Enable circuits | 19 |
| CY storage | 3 |
| ALU enable | 4 |
| Total | 92 |
ALU board:
Photo of completed ALU:
Registers module
Relays required for registers:
| Component | Number of relays |
|---|---|
| Data | 64 |
| Load | 8 |
| Data enable | 32 |
| Address enable | 8 |
| Total | 112 |
| Without PC | 97 |
| Program counter | 15 |
Registers board
Control board
Memory board
