Roff
Well-Known Member
Can you get a 2N5550 to replace the 2N2222?Ron,
Thanks for spending time on this. I am well aware of ones "spare time"
If you go back to the beginning of this thread, these components were given to me by various people. I think Eric might have been the guy who rec'md the 2N2222.
I will use my own 8V Vreg, or the one posted a page back. (Although not sure why I need an adj one.)
If you read the text where I posted the regulator, you'll see that I recommended 78L08 or LM317L. If you use 78L08, the cap on the input side needs to be 330nF instead of 100nF. 330nF should also work for LM317L.
The MOSFET would replace the NPN. You would actually save a couple of parts (the 100k divider), but the MOSFET I have in mind is surface mount.I think using both sides of the LM393 is just as good. A MOSFET would require adding in another component which takes away board real estate.
LMK???I am going to start over and make all new boards. I will order any new stuff from digikey. So if you feel that other components are worth changing, LMK and I will order those as well.
Please verify components:
U1 = POT 1K?
U3 = POT 500K? (adj Hysteresis )
LM393 Vcc = 8V ? ( I assume since you have an "8" below the Vreg symbol.
The pot values are correct.
The schematic shows power pins on both LM393 sections. This is so the simulation will run. See the LM393 datasheet for pinout.
The 1k pot sets the low side of the hysteresis range. The range of adjustment is nominally 3.3V to 4.0V. You said you wanted 3.65V. This voltage is independent of the 500k pot setting. It will change when the relay coil is energized, but is not relevant during this time.
The 500k pot does adjust hysteresis, but you might want to think of it as the threshold adjustment. The range is nominally 4.4V to 4.9V, subject to component tolerances.
The zener is not needed. The 8V regulator is a better reference than the zener.Lastly, I do not see any Zener's here. Does this new design eliminate them? Since adjusting the Vsrc is so limited for my usage (4.0 to 4.7 range)
I believe it's complete except for the aforementioned voltage regulator, which is posted on the previous page. You should also add 100nF caps from LM393 pin 8 to GND, and from the terminal of the relay coil that connects to the battery.Lastly, this new circuit above, is it totally complete? I ask because the configuration on R1 and R2 is different than my original that has caps and Zener's to the left.
You obviously should not commit to large quantities before you test the design.