strokedmaro
New Member
I'm having difficulties getting this IC to work on my breadboard. I think its partially due to the fact that I don't fully understand the datasheet. This is a single channel (1 button) IC but the datasheet does not show what value to use for "RE" and I'm not sure if "Cx" is an actual cap or not. It also does not accurately describe how the electrode is made. Ive seen other electrode designs and they are almost always 2 contacts (like a circle inside another circle physically seperated with a gap between them) but the data sheet shows it more like a single electrode.
Anyway, I have it setup like figure 1-1 in the datasheet using cap's of the valve suggested in the paragraph below the diagram. (10nF and 10pF) "CX" is grounded as pictured and the electrode is basically a strip of 5 breadboard inputs. What I find odd is im using an led on pin 2 to show when the switch is made and it is constantly on. When I put my finger over the "electrode", nothing happens...it remains on. (This I'm sure is due to the tiny surface area of my current breadboard electrode) However, when I touch the leads of either resistor the LED goes out and comes back on about 3-4 seconds after I remove my finger. I would have thought that the LED would be out as long as I did not activate the switch. It works like a normally closed switch at the moment and requires me to physically touch it like a resistive touch IC.
Im using 470k resistors for Rs and Re, caps as described earlier and a V reg. putting out 4.5 vdc. Any help appreciated!!
DATASHEET: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=427-1091-ND
Anyway, I have it setup like figure 1-1 in the datasheet using cap's of the valve suggested in the paragraph below the diagram. (10nF and 10pF) "CX" is grounded as pictured and the electrode is basically a strip of 5 breadboard inputs. What I find odd is im using an led on pin 2 to show when the switch is made and it is constantly on. When I put my finger over the "electrode", nothing happens...it remains on. (This I'm sure is due to the tiny surface area of my current breadboard electrode) However, when I touch the leads of either resistor the LED goes out and comes back on about 3-4 seconds after I remove my finger. I would have thought that the LED would be out as long as I did not activate the switch. It works like a normally closed switch at the moment and requires me to physically touch it like a resistive touch IC.
Im using 470k resistors for Rs and Re, caps as described earlier and a V reg. putting out 4.5 vdc. Any help appreciated!!
DATASHEET: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=427-1091-ND
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