Prince Charming
Member level 2

Hello, I've been developing a motion alarm system as below:
There is the C5 capacitor (470uF) which let's the user turn on the system and leave the place without triggering it by their own. It works by not letting current from data line for a period of time after turn on. The problem is, I want to fully discharge that capacitor when power is cut (to restart the timer). I could only think of N channel depletion MOSFET. But the problem is, is there any depletion MOSFETs out there or is it just a myth
, no matter what I tried, I couldn't find one. So I would be glad if I could get these 3 things:
1 - Common depletion MOSFET models (not only for this project)
2 - Any other way to discharge the cap
3 - (if you really want to take time and look) Any suggestions to circuit as a whole. The upper circuit is the UPS and the bottom is the alarm triggering circuit.
Thanks.
There is the C5 capacitor (470uF) which let's the user turn on the system and leave the place without triggering it by their own. It works by not letting current from data line for a period of time after turn on. The problem is, I want to fully discharge that capacitor when power is cut (to restart the timer). I could only think of N channel depletion MOSFET. But the problem is, is there any depletion MOSFETs out there or is it just a myth
1 - Common depletion MOSFET models (not only for this project)
2 - Any other way to discharge the cap
3 - (if you really want to take time and look) Any suggestions to circuit as a whole. The upper circuit is the UPS and the bottom is the alarm triggering circuit.
Thanks.