Re: Suspension losses

On 1/4/2025 3:28 PM, Frank Krygowski wrote:

On 1/4/2025 2:52 PM, AMuzi wrote:

On 1/4/2025 1:36 PM, Jeff Liebermann wrote:

On Sat, 4 Jan 2025 12:35:20 -0600, AMuzi <am@yellowjersey.org> wrote:
>
User manual on an early analog computer including a few useful
examples.  Try to visualize what those problems might look like on a
slide rule or today's personal computers:
<https://www.analogmuseum.org/english/collection/eai/tr10/>
<https://www.analogmuseum.org/library/eai_tr-10.pdf>

>
Ah, such as a slide rule. Got it, thanks.

 The device I was talking about was nothing like a slide rule. It looked vaguely like the one in Jeff's last link above, but the classroom demonstrator was much larger - maybe 3' x 4' IIRC - with much bigger knobs (4" diameter?) and meters.
 We were talking about electrical analogies for vibrating masses, and that's one of the things the analog computer could simulate. One would have to calculate the values of voltage, inductance and resistance to correctly simulate the damped spring-mass system, set initial conditions, then let the circuit run. The system's meters would then swing back and forth in a manner analogous to the position of the mass. All this was before digital computers were desktop devices.
 (In those days, the programs I wrote for vaguely similar problems were room sized and run by full time technicians, and I'd turn in a program stored as a thick deck of punched cards, hoping output would be ready the next day.)
 As I recall, we students never did any actual work with that analog computer.
 

Right.  The values shown on that meter with a swinging needle are analog, not digital; the scale and range can approximate the value to an acceptable degree without a specific digital value.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971