3 ms·
Relay contacts tend to spark when they engage each other. You can get rid of most of that sparking by adding diodes but that would be cheating (semiconductors a
by 0x12 15y ago
Relay contacts tend to spark when they engage each other. You can get rid of most of that sparking by adding diodes but that would be cheating (semiconductors again), to a lesser extent using small neon bulbs across the coils (that will still take them up to 90V though).
With 'practical' I meant that you would be able to run programs to completion for for instance numerical problems.
Vacuum tube computers suffer from different problems (such as tube filaments burning out) and I really wonder whether a well designed vacuum tube computer would be more or less reliable than a well designed relay based computer.
Vacuum tubes got awfully small in their final days but the voltages involved and the heat make me believe that relays would probably be more reliable, but likely also more expensive and much slower.
- stan_rogers 15y agoA capacitor will deal with the sparking -- they've been used (under the name condenser) in conjunction with points and mechanical distributors in internal combustion engines for years. This all presupposes a memory of methods to create reliable electricity, though -- including rectification and filtering, if that memory involves alternators. A purely mechanical representation of computing would probably be more practical in a forced Iron Age reboot of society. A treadmill-powered version of Photoshop would be a bitch, of course, but number crunching (at the level needed for serious societal progress) would come fairly quickly.
- JoshTriplett 15y agoThe relay computer does use a capacitor: a huge 1F capacitor.
- 0x12 15y agoThat's to stabilize the power supply, not to help with avoiding contact erosion.