Hi , working on building an analog tach using the "current" circuit recommended on the National Semiconductor datasheet. The circuit has a diode connected to pin 11. The signal I need to count goes from about +1 volt to about +13 volts. Using the diode I'm thinking will require the input go below .7 volts to count. The datasheet says I can set the comparator input level but can't figure out how it's done. Would I want to set the comparator to about +6 volts and how could I do that? Any suggestions?