Hi Marc, just take a look at the block diagramm of the circuit http://www.fairchildsemi.com/ds/NE/NE555.pdf
On Thursday 19 January 2006 22:02, Marc wrote: > ne555 timer > > 1 gnd = pwr > 2 trigger = > 3 output = out > 4 reset = > 5 control v = > 6 threshold = > 7 discharge = > 8 vcc = pwr Trigger is a high impedanz OPV input --> input Threshold too --> input Discharge has a transistor with open collector --> open collector Reset is a transistor basis --> I'd suggest input or passiv here Control voltage has a 2/3 voltage divider --> passiv > what should the following pintypes be set to pls > and what if a pin is unused on a chip what do you set it as If a pin is not connected use passiv. This is in my opinion the savest option as a DRC should not complain about it if you connect it for example to a different signal for cooling, mounting, ... reasons. regards Werner
