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Topic: CHALLENGE QUESTION TWO
Replies: 8   Last Post: Jul 21, 1996 2:04 PM

 Messages: [ Previous | Next ]
 Helmut Forren Posts: 2 Registered: 12/12/04
CHALLENGE QUESTION TWO
Posted: Jul 19, 1996 2:44 AM

HERE IS A CHALLENGE DESIGN QUESTION.
ANYONE WITH A GOOD WORKABLE SOLUTION WILL BE WELL REWARDED.
PLEASE RESPOND DIRECTLY TO ME VIA EMAIL, AND PERHAPS ALSO WITH A POST

I have the following circuit:

(Switched Voltage) VS
|
R1
|
+----+---- (Output) VO
| |
C R3
| |
+----+
|
(Ground)

The switched voltage VS is alternated between a reference, VR,
and ground. When switched to VS, the circuit charges C and VO
rises. When VO reaches 2/3 of VR, the circuit is automatically
switched to ground and begins to discharge C. When C reaches
1/3 of VR, the circuit is automatically switched back to VR and
the cycle repeats.

The objective is to determine the value that VO would reach when
VS is switched to VR and C is missing (same as if infinite time
has passed). Unfortunately, this value can not be measured directly.
Instead, I can only measure the time that it takes for VO to independently
charge or discharge between 1/3 and 2/3 of VR (VR known if necessary).

Assume that the values of R1 and R3 are such that VO actually
reaches 2/3 of VR, and in a quick time frame.

Approximations must be proven to be within better than 0.1%, otherwise
they should be avoided.

Date Subject Author
7/19/96 Helmut Forren
7/19/96 Christopher Curtis Dudman
7/19/96 James P. Meyer
7/19/96 Frank Bemelman
7/19/96 Richard and/or Clay
7/21/96 krw@together.net
7/20/96 Winfield Hill
7/20/96 Joseph Riel
7/21/96 Sam Goldwasser