Schmitt trigger issue

e:

te:

:

rote:

rote:

t I had to put

t a second

rking, but

left of the

ive-going pulse

e a

from a

Q15 latches

cating the

might be a

he logic NAND

of R82 and

tary resets

eset the

orms are on

nual..pdf

is not

is wrong?

ched into the

lasts of noise

" mode, which

contact, but

g indicates

pins 7 and 8

4 and FF pin

ake sense.

e

n 4 and 2

bit of

e schematic is pretty clear on showing the FF operation as what you are obs erving when the plug is removed from the socket.

. With the

er, the

ed, there

leeve, a movable plug tip contact (the notched piece), and an internal SPDT switch between terminals 8, 7- and why they don't number the friggin pole I don't know! The bent piece on terminal 7 is meant to show a NC connection with the pole with the plug out of the jack, and it clearly shows the inte rnal pole is connected to tip (6) with the plug out of the jack. With the p lug out of the jack, the operation of the START and STOP switches runs the show, turning the clock oscillator on and off and some other stuff. With th e plug in the jack the FOOT SW runs the show, the TIP to internal SPDT pole connection is broken as is 7 to internal switch pole. This prevents the ST ART and STOP switches from latching the FF and it also gives the FOOT SW co mplete control over gating the clock oscillator, turning it on when FOOT cl oses and turning it off when it opens.

onnected

f the

tact

y to interpret the schematic and I told you what it is. How difficult is it to understand that 1) with plug removed, circuit operation is push on/ pus h off thru START/STOP switches and 2) when plug is inserted into jack, circ uit is ON (MOMENTARY)/OFF through the FOOT SW ( a SPST to shield GND).

tacts

ols are

tact

nd every

ans it connects!

ated

ip and show the pole contact making NC contact with the bottom throw by ben ding the pole contact and not the throw contact. The reason they bent the t hrow contact is because they want that pole connection horizontal and makin g contact with the TIP, the usual schematic for a phone plug type jack.

h multiple isolated switches. All you need to know is that whatever switch position is shown with plug removed, the jack only schematic, all of that g ets flipped when the plug is inserted: what was open gets closed and vice v ersa, the double throws get flipped, the NCs go open and the NOs go closed, etc....

k.

k

ew

e

for 2 x Tpd until it latches logic low thru the FF preventing C45 from re- charging. The IC is a 4011UB, output is safely current limited.

You don't know anything about 4000 series CMOS.