So I want to trigger a monostable 555 to fire when a capacitor raises above 0.5 volts. My plan was to use a Zener diode to bias an NPN transistor that would trigger the 555. But I discovered the smallest zener voltage you can buy is 1.8 Volts.
Is there any way I can somehow bias the zener to react to a lower reverse voltage than its actual threshold?
Does someone have a better idea on how to get the 555 to trigger when intended?
ASIDE: I would also be satisfied with having the 555 trigger when the capacitor drops below 0.5 volts. I don't think it matters to me if it's going up or down, just so long as I can make the trigger at the stated voltage (very close to zero). The purpose is I'm trying to trip the 555 at some point where the cap is very close to zero volts.