Hello,

On Mon, Feb 07, 2005 at 09:04:20AM +0100, ThePicMan wrote:
> 
> I'm no analog expert as well, but to me the left-side of your schematic is
> unnecessarily complex. Why not make it like this (ASCII art):
> 
> 
>                        |\ | 1N4148
> RTS--------------------| >|----------.
> (low, i.e. +12V)       |/ |          |
>                                      /
>                                      \ 100 ohm
>                                      /
>                                      \
>                                      /
>                                      |
> CD-----------------------------------*----- 5
>                                                4N27
>                                      .----- 4
>                                      |
>                                      |
>                                      |
>                                      |
>                                      |
> DTR----------------------------------'
> (high, i.e. -12V)
> 
> at least that's how I'm doing it (you may want to check the thread
> "[EE] Poor man's very low frequency oscilloscope.").

What I'm trying to do is low-pass filter the output from the opto so that CD
only goes low after a couple missed AC cycles. I don't want a fluctuating
output. You got me thinking though, maybe if the AC side is full-wave
rectified and a suitable capacitor is used across the LED pins of the opto,
I could use the circuit you diagrammed above. It's something to try.

Take care, Matthew.

-- 
"This isn't right, this isn't even wrong." -- Wolfgang Pauli
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