Viewmaster wrote:How about someone designing the motor control PLL using valves?
Albert.
Well, it could be done. If you wanted a vacuum-state version of the part of the 4046 so commonly used it would require about six 5965 or ECC88 valves, both of which are listed as for use in computers! The part of the 4046 used here is just four flip-flops and some output drivers.
This then feeds something like a EL34 or EL37 as the output device. One of the hardest things might be getting DC motors that run on a few hundred Volts!
I agree, LEDs would be a no-no. A large bulbous Neon please! Attached pic is about the best I can find at the moment.
Steve A.
When it comes to tube computing the two most famous are the 'Colossus' at Bletchly Park, and the Eniac in the US.
Colossus was the size of a living room and weighed about one tonne. Its 2,400 valves replicated the pattern of an encrypted Lorenz message as electrical signals. This breakthrough in computing remained a secret for many years, to the extent that two Americans took the credit for inventing the computer in 1945.
By today's standards for electronic computers the ENIAC was a grotesque monster. Its thirty separate units, plus power supply and forced-air cooling, weighed over thirty tons. Its 19,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors consumed almost 200 kilowatts of electrical power.
Now run that lot off your laptop battery!
...just as a bit of trivia, I did some number-crunching and the battery in my laptop would power Eniac for 250 micro-seconds!!!!