January 2017 63
process while doing other work on
the other screen.
Ann Arbor, MI
#2 Quite easy to do. You need
to get a cable to go from the RCA
jacks on your cassette deck to a
stereo mini plug to go into your PC.
Very common, but if you can’t find
one, then Amazon has them. Dynex
A20420 and many others. For your
purposes, practically anything will do.
Then, download Audacity, which
(in my humble opinion) is the best
audio editing program out there —
especially since it is free. Go to www.
audacityteam.org for the details.
For MP3 export, you’ll also need
something called LAME, available on
the Audacity site. Play your tapes into
Audacity, then export them either as
single songs per file or entire sides.
For that matter, you can capture both
sides of the tape and use Audacity
to remove the dead areas that occur
while changing sides. Or, if you only
like a couple of the songs, just copy
and paste what you want.
[#10161 - October 2016]
My desk fan has a three-position
switch: HI/OFF/LOW. I would like to
convert the fan to variable speed. Will
a simple lamp dimmer work for this
#1 Please do not even think of
using a simple lamp dimmer for this!
Lamp dimmers are for
incandescent (filament) bulbs only —
not inductive motor (AC or DC) loads
— and will likely cause a fire! A lamp
dimmer connected to a ceiling fan
caused such a fire, nearly burning my
neighbor’s house down! Don’t do it.
The easiest, cheapest, and safest
solution is readily available from
Harbor Freight Tools. Item 43060
is a “Router Speed Control” and
works great with inductive AC or DC
motors up to 15 amps (120 VAC).
I have several to vary the speed
of many tools, not just my router.
Costing about $15 a piece, I use this
controller with my five-speed wood
drill press (when drilling soft metals
that require slower speeds); with
Harbor Freight’s largest “hurricane”
fan (which also has a HI/MED/LOW/
OFF switch); and other AC powered
fixed speed tools.
Equipped with a 15 amp
3AG type fuse and a three-prong
receptacle, this lightweight controller
is hard to beat and much safer to use.
BGood Will KD2FZU
#2 Danger Danger! The typical
lamp dimmer is not compatible with
the typical cheap fan motor. There
are good articles on the Web as to
why. Look up shaded pole speed
control and see why. That said, I find
that box fan motors tend to be okay
with better (triac based) motor speed
controllers, such as sold by Harbor
Freight and on eBay. On a shaded
pole motor of a typical cheap fan,
overheating the motor is possible.
[#9164 - September 2016]
I’m retired and re-learning
electronics. I am confused about the
differences between MOSFET and
“regular” transistors. Is there a rule of
thumb as to when/where/why you
would use one over the other?
Traditionally, MOSFETS were used
for small-signal amplifiers and mixers,
particularly at high frequencies. High
currents or voltages would easily burn
them out. Today, there are power
MOSFETS but they aren’t very fast. So
the existing MOSFETS tend to fall in
two families: Fast but fragile, or strong
but slow. Kind of like people.
[#10162 - October 2016]
Fish Caller Circuit
I found a partially assembled kit
labeled “Fish Caller.” Does anyone
have a schematic for one that I could
use to finish it? Also, what’s the theory
behind how it works ... or does it?
#1 Seriously, you can find all the
circuits you want by Googling “Fish
Caller Circuit” and looking at the
images. Less than seriously, it emits
Fishy Language for “Neener, neener,
neener! You can’t catch me!”
#2 I built one years ago. It was
designed to produce a high frequency
noise that supposedly attracted fish.
Maybe my fish were hard of hearing
but it never worked in my field trials.
I have never seen them promoted in
any fishing supply catalogs either.
#3 Theory: It makes a ticking
sound that sounds like a dying fish
which attracts other fish.
You might try https://www.
electronickits.com/electronic-fish-caller-plan. On the other hand, if all
it does is tick, you now know what
the circuit is supposed to do and you
might be able to complete it with just
that much information. The above link
sells plans to build such a thing. There
are others selling kits as well. I simply
did a web search to find the above.
Mt Airy, MD
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