I'd suggest a high-side switch. The HC-12 needs up to 200mA, depending on transmit power level, but can work OK down to 3.2 volts. So a small signal NPN (Eg BC548 or equivalent) driving a slightly stronger PNP (Try a BC327 or equivalent) should do the trick.Hi AllyCat,
Thank you for your remarks. I have checked the power consumtion 08M2 and get the following:
pause M16 1.14 mA
K250 0.27 mA
sleep M16 0.07 mA
K250 0.07 mA
So it seems that the job is to reduce the power consumption of HC-12 and the H-bridge/valve.
I am trying a transistor switch for that - without much luck so far.
I would use a 1k to 4.7k resistor for R1. Try 4.7k for R2 - this can be reduced as low as 1k if Q2 does not turn on sufficiently. R3 is just to ensure that Q2 turns off fully, so I'd use 10k.Hi inglewoodpete and AllyCat,
I am at the moment looking at activating a H-Bridge/valve and for that I need the high-side switch.
Can one say something about the values of R1, R2 and R3 when the load resistance is 5 kOhm? Actually one of the H-Bridges I might use shows OL for the resistance between the + and - terminals.
I think that I have cooked some transistors and would like to start with reasonable values.
No pulse Pulse v v mA Q1 Base 0.000 0.727 Coll 0.056 3.098 Q2 Base 3.868 3.446 7.25 Emitt 4.590 4.300 257 Coll 0.001 4.100 257
That is a CURRENT equation so can tell you little about voltage drops. What Q2 are you using?Can I get Connector = Emitter voltage given the equation Ic = Ie - Ib
You have remember that any transistor is a SEMI-conductor, so will never have zero resistance. As Alan says, very low 'on' resistance can be achieved with a suitable MOSFET but selecting a suitable one can be a challenge.My question is: Can I get Connector = Emitter voltage given the equation Ic = Ie - Ib or will I always have to accept a difference? How small can I get it? Is it worth going for the last 0.1 v?
A "year" of 7 months. Presumably the "cold" ones, or when there's insufficient solar power?.... should give a consumption of appr. 0.60 x 24 x 30 x 7/1000 Ah = 3 Ah for a year. That should be alright.