BlinkingLeds
- Feb 23, 2013
- 180
- Joined
- Feb 23, 2013
- Messages
- 180
This is a DC Transfer Characteristic Analysis with Hysteresis included. Hysteresis (if any) is analyzed by the following....
VF2 sweeps from 9V to 0V. VF2 then sweeps from 0V to 9V. So, the VF1 plot you see reflects U1's output going High when the Trigger pin voltage (VF2) falls below 3V. This is the left VF1 transition from 0V to 8.79V. The transition you're questioning occurs when the VF2 sweep reaches 6V on the ramp's up slope the output (VF1) switches back to 0V. This happens because the Threshold pin responds to voltages >= 2/3 VCC. Since the Trigger and Threshold pins are tied together we get the output pin response of both pin's characteristcs. In short it's hysteresis that you see there and that's what's confusing you.
Chris
Ok thanks that clarifies it, i'l hook it up on the breadboard and update.
Thanks again.
regards