Electronics Forum / Basics / October 2007

I setup a mosfet to switch power to a pin on a PIC. The circuit works only
for low R.
Vcc ---> R ----> Drain + link to pic
Source ---> GND

I am looking for MRD500 photodiode.
Does anyone can advice me where can I get this part.
Thanks in advance.
Alexander .

G'day all
I've designed and am in the process of making a speaker emulator for Pro
Audio recording application
and would like to add preset memory and midi program change to the unit.

I had an older model Dremel (260) rotary tool throw a brush, which
shorted out and fried the switch assembly.  Repair parts are no longer
available for this model.  I can replace the slide switch, but
replacing the 3/4"x1/2"x1/4' black electronic component that is part

I'm building a power supply for a 36V, 500W DC motor to drive a small
lathe.
I have scrounged a transformer from an old microwave oven and removed
the 2000V secondary windings leaving the 240V primary windings intact

I'm setting up a small CNC mill to educate myself before taking the plunge
on a larger machine and I have a few questions about the stepper motors and
stepper driver boards.
Firstly, the motors have what looks like 7/0.2 wires attached and according

I'm a EE student at Cornell working on a research project.  We have to
do a significant amount of hand soldering for the project.  Which chip
packages are hand solderable?  I need to know what I can purchase
from, say, DigiKey and actually solder.  Examples of packages I'm

Can someone explain what the REF pin on my DAC is for?
It's an input voltage reference that can be GND, Vdd-1.5 or nominally
2.048v at Vdd =5v.
What is this voltage used for?

Does anyone have a link to any tutorials for PIC assembly?
Over the past few months I've been trying many permutations of Google search
string, but most of the tutorials I've found assume previous experience at
writing assy for microprocessors.

Hello, I am now looking for an Operation Amplifer chip able to be a
voltage follower, which I need to use as a buffer between my sensor
circuit and the digitizer. Can anybody help me?
Since the output impedance of my sensor circuit is about 0.2 Gohm, the

i have a circuit board that appears to have had some mods done as
components do not match or blend with other components.
my concern for now is two polarized electrolytic caps that appear
to be used as "bypass caps" ??

i am working on an old mid 80's circuit board  that has some
original 2200 uF/ 63V electrolytic caps (size of a C-cell) plus
some others and was just wondering when one should just replace
such a creature ?

I live across the street from this family with 20-some year old "kids"
who, I suspect, frequently throws things out their car windows onto my
lawn and my driveway.  I'm almost sure it's them, but I want video to
prove it.  I think my best option would be a small, low cost B/W

I built a circuit from this link:
http://ourworld.compuserve.com/homepages/bill_bowden/page9.htm
entitled "High Current Mosfet toggle switch with debounced push
button.  It worked perfectly on the breadboard.  When I installed it

I am trying to find out who manufactures a chip, two actually.  One chip
has the logo "MX" on it and the other has "MIRA".  The numbers on
the "MX" chip are "mq44305, 29lv160bbtc-90 which I suspect is a 16Mb
ram chip.  The other one is marked "MIRA" and has P2V64S40DTP and