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I've been doing some restoration on an analog computer. While it seems bizarre now to solve a problem with analog circuits instead of a digital computer, analog
by kens 6y ago
I've been doing some restoration on an analog computer. While it seems bizarre now to solve a problem with analog circuits instead of a digital computer, analog computers were a reasonable approach until about the 1970s.
The basic idea of an analog computer is you use op amps to sum voltages. Integration is easy, by adding a capacitor. By hooking up op amps, capacitors, and resistors (usually with a plugboard), you can quickly and easily solve differential equations. (Surprisingly, multiplication by a non-constant value is hard with an analog computer.)
The nice thing about analog computers is they gave the answer almost instantaneously. You could turn the dials and experiment with different parameters interactively. A digital computer in 1970, on the other hand, might take minutes to solve the same equation. This also made analog computers useful for real-time applications such as flight simulators.
A big problem with analog computers is that the accuracy is limited by your components. If you want 0.1% accuracy, you need expensive 0.1% resistors and capacitors. With a digital computer, you can get as many bits of accuracy as you want using cheap components. Basically, Moore's law killed off analog computers.
- TrackerFF 6y agoJust fire up any older electronics textbook, and they'll probably have examples of integrator and summing circuits solving differential equations. At least that's what we had in our control (engineering) books.
- sudosysgen 6y agoIn my dad's Calculus II equivalent class in Morocco, one of the question in their exam was to built the circuit to solve a given differential equation. Pretty neat! That being said, that exam was substantially shorter and easier than the Cal II exam I had to take!
- qppo 6y ago> multiplication by a non-constant value is hard with an analog computer Researching this topic also qualifies you to write technobabble for sci-fi movies. Like "operational trans impedance amplifier."
- andreareina 6y agoIf you haven't seen it yet, the retroencabultaor video [1] is a masterclass on how to do it. [1] https://youtu.be/RXJKdh1KZ0w https://youtu.be/RXJKdh1KZ0w
- nullsense 6y agoThe original too! https://youtu.be/Ac7G7xOG2Ag https://youtu.be/Ac7G7xOG2Ag
- elcritch 6y agoI actually use a transimpedance amplifier for my work, and it’s even operational most of the time! But one does wonder if techno-babble really does sound like real techno jargon to none experts.