On 24 Nov 2005 06:58:27 GMT, (Michael Black)
wrote:

) writes:
On 22 Nov 2005 21:41:19 GMT, (Steven Swift) wrote:

Pretty good. Did a similar thing using 3 555s. One was used as a
threshold detector, one for the Onshot (with a FET constant current
source) and one for the retrigger holdoff oneshot. Worked to well
to beyond the 5mhz scope it was used with.

Allison

And as I pointed out in the previous thread, that wave thirty years
ago of adding triggered sweep to older scopes did all use 555s for
the ramp generator.

I cleared off the scanner, and
http://www.cam.org/~blackm00/ramp.jpg
is the scan out of Howard Berlin's "The 555 Timer Applications Sourcebook
with Experiments" from 1976. The actual circuit was originally in Electronics
magazine for October 11, 1973, which I likely do have (at least
the part with the circuit) somewhere but can't be bothered looking.

And as I said, this basic circuit did seem to be the basis of
all those "add triggered sweep to your oscilliscope" articles
from thirty years ago. As I recall, they were all basically like
this one.

Michael VE2BVW

It was 1972 when I first did the 555 thing. The basic circuit was
greatly improved over the one shown in the URL. But the idea
was the same. The 555 is an interesting chip and does real well
for things like threshold detection and any form of timing or timing
related functions.

Allison