"John Fields" wrote in message
...
On Thu, 13 Oct 2011 16:37:32 -0500, "Dave" wrote:


"John Fields" wrote in message
. ..
On Wed, 12 Oct 2011 21:04:52 -0500, "Dave" wrote:


"John Fields" wrote in message
m...
On Wed, 12 Oct 2011 16:44:41 -0500, "Dave" wrote:

Hey John. No, I don't have any data on the PV (I'm guessing that is
"PhotoVoataic".) It's something I pulled out of my junkbox...

---
PhotoVoltaic. :-)
^
---

BTW, I'm trying to run this sim in LTSpice, and can't figure out how
to
make
it work. This is a netlist, right?

---
No.

It's an ASCII circuit description, and LTspice generates the needed
netlist from it.
---

How can I import it to my version of LTSpice and give it a test run.
I'm really interested in seeing your changes.
Thanks!

---
OK.

Save the list to a file and name it anything you like as long as it
has a .asc extension, say, "nightlight.asc".

Then, invoke LTspice, navigate to the file and left click on it.

Voila! The beautemous schematic will appear before your very eyes,
ready to be run and probed :-)

BTW, the X axis of the waveform viewer is set to correspond to a 24
hour day and you can adjust the voltage divider connected to the BJT's
base to set the circuit's switching threshold to a function of time by
regarding voltage as a function of irradiance.
--
JF

THANK YOU! *Much appreciated.*

Dave

---
My pleasure. :-)

--
JF

Hey John, have a question RE the Spice schematic generated by the netlist
which resulted from opening the ASCII circuit description you posted. The
schematic shows V3, or the PV, as being four volts, not four hundred
millivolts, which would accurately describe the real circuit I am working
with. If I said that the PV generated 4 volts, I was full of crap. It is
.4V. Seems like this would change everything. But that's why I had a
4.2K
in series with a 680 Ohm resistor for the voltage divider that drives the
base of Q1. When I saw you had a 4.7K and a 10K for those resistors, I
knew
something was not right. Please give this another glance, and let me know
what you think...

---
You won't have enough gain with a single transistor and only 400mV
deltaV on the base to get crispy switch points, but change R3 to 1K
and R4 to 240 ohms and you'll at least get the LED to turn on and off
as day turns to night turns to day.

Have you tried Doctor Phil's circuit yet?

--
JF

Haven't received the parts I ordered from Digikey yet. Maybe tomorrow or
Saturday...

And the 400 mV is coming from the tiny photocell, to counter part of the
voltage divider's voltage at the base and turn Q1 off when the sun is
shining.

Dave