Completely Analog Circuit for playing Ping Pong on Oscilloscope

[raymondtco]

Hi All,

I am building a Completely Analog Circuit for playing Ping Pong on Oscilloscope (Tennis for two) from scratch (resistors, capacitors, op amps, and JFETs).

I am stuck on the fact that, since I want to include the gravity by two integrators (to generate the 1/2 gt^2 term in kinematic equation), the capacitors in the integrators will be fully charged after a period of time.

Do you guys have any idea how to go about this issue by using resistors, capacitors, op amps, and JFETs?

I found this schematic but I can't understand some of the notations, such as a bar wound by a wire (inductor?) and a line sandwiched by two arrows.

Tennis For Two


Thanks a lot!!

 

[ericgibbs]

Hi All,

I am building a Completely Analog Circuit for playing Ping Pong on Oscilloscope (Tennis for two) from scratch (resistors, capacitors, op amps, and JFETs).

I am stuck on the fact that, since I want to include the gravity by two integrators (to generate the 1/2 gt^2 term in kinematic equation), the capacitors in the integrators will be fully charged after a period of time.

Do you guys have any idea how to go about this issue by using resistors, capacitors, op amps, and JFETs?

I found this schematic but I can't understand some of the notations, such as a bar wound by a wire (inductor?) and a line sandwiched by two arrows.

Tennis For Two


Thanks a lot!!

hi,
The bar wound are relays, a number of different types are specified.
Have you seen the date of the drawings, looks like 1959.!!

 

[Mikebits]

Wow that is old. So what are the symbols that look like buffers?

 

[Pommie]

Wow that is old. So what are the symbols that look like buffers?

My guess would be inverting opamps.

Mike.

 

[Mikebits]

I thought they did not have op amps in 1959? Aside from the tube version...

---------------------edit-----------------
Had to check, FYI
https://en.wikipedia.org/wiki/Operational_amplifier#History

 

[ericgibbs]

I thought they did not have op amps in 1959? Aside from the tube version...

---------------------edit-----------------
Had to check, FYI
Operational amplifier - Wikipedia, the free encyclopedia

hi,
We used to make our own OPA's using transistors...

 

[Mikebits]

But... In 1959 ??? Really! I had no idea. I guess I learned something today.

 

[Pommie]

I was -1 at the time so I've not got a clue. However, to make an integrator without an opamp would be pretty tricky. So they must have had them even if they were fabricated from individual components.

Mike.

 

[ericgibbs]

I was -1 at the time so I've not got a clue. However, to make an integrator without an opamp would be pretty tricky. So they must have had them even if they were fabricated from individual components.

Mike.

hi Mike,
At British Steel we used to make analog computers using either early transistors or valves.

 

[Mikebits]

So the amp symbols must be a form of a hierarchical design, so a page showing the amp config must be missing. Did you see the bistable on page 2 and did you note the text that said to computer. What computer did they have in 59 the ENIAC? A pretty historical schematic

Oops, sorry if I took the post off topic.

 

[Nigel Goodwin]

hi Mike,
At British Steel we used to make analog computers using either early transistors or valves.

Which of course is where opamps came from, as the central part of analogue computers - long before IC's.

 

[Mikebits]

Which of course is where opamps came from, as the central part of analogue computers - long before IC's.

I had to look up analog, or analogue computers. Did you know the slide rule was considered a analog computer.

 

[ericgibbs]

I had to look up analog, or analogue computers. Did you know the slide rule was considered a analog computer.

Yes, but did you know the WW2 Spitfire was designed using a slide rule..

Its not the tools that gets the job done, its the guy who is using the tools..

 

[Nigel Goodwin]

I had to look up analog, or analogue computers. Did you know the slide rule was considered a analog computer.

Yes, but I always hated slide rules!

To make matters worse, as I was always friendly with the woodwork teacher, I got assigned to build a 6 foot long slide rule for the maths department - just wood covered with Formica - the maths department were going to mark it.