[sdiy] Revision of Analysis of Buchla 259 principal oscillator

[Aaron Lanterman]

A kind soul pointed out that the smudge I thought was a 20.7K resistor was 
really a 28.7K resistor.

There's a resistor setup...

                   15 V
                     |
                   28.7K
                     |
                     |
vtri ---- 4.99K ----+-- v-

Let's find out what values of vo will trip the comparitor.

By the usual resistive divider setup:

v- = (vtri 28.7 + 15 * 4.99) / (28.7 + 4.99)

v- = vtri 0.8519 + 2.2217

The comparitor trips at 0 and 4.29 V. This corresponds to tripping at

vtri = (0 - 2.2217) / 0.8519 = -2.608

vtri = (4.29 - 2.2217) / 0.8519 = 2.4279

Ah, OK, that's more like it, just a DC offset of -0.1 v or so.

Still thinking about what that 7.V is doing on IC20.

- Aaron

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Dr. Aaron Lanterman, Asst. Prof.       Voice:  404-385-2548
School of Electrical and Comp. Eng.    Fax:    404-894-8363
Georgia Institute of Technology        E-mail: lanterma at ece.gatech.edu
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