PWM project for tiny DC motor turning painting

[John Popelish]

Michael Eisenstadt wrote:

John Popelish wrote:

I wrote:

If I understand you aright, and having tested with the multimeter, the
center terminal should be connected to R1 resistor, one outer terminal
to C2 capacitor

John Popelish wrote:

All those get connected together.

I'm not entirely following you here.

and the other outer terminal to pins 3, 5 & 6 of the
NAND Gate. Is that right?

Yes.

Have I wired the pot's terminals correctly? I am asking before
soldering the 3 connections.

Please refer to schematic and picture at
http://charlesumlauf.com/PWMproject.htm

Again thanks for your indispensable help.

Look at the schematic. There are two nodes associated with R2. One
of those nodes is the bottom of the resistive element in R2, the
wiper, the bottom of C2 and the bottom of R1. So all these points
need to be connected together (plugged into a vertical set of 5
connected holes in the proto board or some other way with jumpers). I
see that you did not put three wires on the pot and use the proto
board ot make all connections, so you will have to add a soldered
jumper between the wiper (center terminal on the pot) and the right
end.

The other node is the top of R2 which connects to pins 3, 5 and 6.
Since these pins will be plugged into three different sets of 5 holes,
you will have to use jumpers to tie these columns together and to R2.
It appears you have these connections made on the board.

--
John Popelish

 

[Freddo Frog]

Another very useful source of hookup wire is get metre (yard) or two of CAT5
cable and strip out the wires.
These are perfect for use in the breadboards.

HTH

"Garrett Mace" <g.ryan@macetech.com> wrote in message
news:mhTQb.103783$VV4.60426@twister.rdc-kc.rr.com...

Thanks for the suggestions about using telephone cable.

Another quick question. In the schematic, the 100k pot's 3
leads connect one of them to resistor R1, another to capacitor
C2 and another to pins 3, 5 and 6 of the CMOS NAND Gate.

The 100k linear pot I bought at Radio Shack (still in bubble pack)
has no markings on the 3 leads. Which lead goes to which connection?


Remember that the two leads tied to C2 and R1 are actually tied together
as
well; by connecting the leads together, the pot is being used as a
rheostat.
The center lead of the pot is the wiper (arrow) and the outer two leads
are
either end of the resistor. It shouldn't matter in this application which
of
the two outer leads goes where.



(Please refer to http://charlesumlauf.com/PWMproject.htm)

Also what kind of socket is needed for the CMOS NAND Gate (mentioned
in the parts list)? I assume that it, like the MOSFET with its
heatsink, needs to dissipate heat.


On a solderless breadboard, no socket should be required. On a solder
board,
I wouldn't use a socket either; logic chips are usually cheaper than
sockets
where I buy them. You can use a socket (on a solder board) if you are
really
concerned that you won't hook the wiring up correctly the first time.
Logic
chips dissipate practically nothing; you won't need a heat sink.