Help Debug Circuit

[ThomsCircuit]

OK, I can fix this. The solution is to add a 5.1 V zener diode across the cap to keep it from charging all the way up to 12 V, and change both R1 and R2 to 47 K. I'll revise the schematic later today. Decent weather - leaves and lights.

Ive read this countless times and while most of it makes logical sense I dont understand why you chose the diode. Im thinking its because of the 2007s gate voltage is just 5v. And to have more control over the timing delays. Perhaps to trick the cap. Yes. The restricted voltage to the cap only allows it to partially charge so this shortens the delay off time. if you say that even without a resistor the delay off would be 1 minute @ 12v i can assume that 5v will reduce it to less than 30 seconds. But the discharge is not to 0v or 0% but to 16% so that time is even less.

Why you chose 47k resistors is not clear. but i can see this timing thing is some guess work and then some math work.
id like to see the equation for the above. it cant be CxR

the voltage changes from 0 V to 2 V. The average is 1 V.

Im looking for ways to understand this so im picking out things that are unclear.
So why does this happen? 0 - 2V

as you can see its puzzling to me but interesting. thank you

 

[ThomsCircuit]

For a signal diode, reverse the connections - anode to the transistor, cathode to the timing capacitor.

Ive done a lot or reading and research. I think i understand what your suggesting as i did not when you initially posted it. The BAT46 is a 100v signal/rectifier diode and is not the same as the zener diode. The zener allows current to flow backwards. So what i have is a signal diode and the instructions wer to insert a zener style in place of the transistor. Being that i only had a signal diode i was inserting it backwards. So the BAT46 should work as long as i insert it as you have outlined above.