#1 Whether you can simply
connect components as shown in
the schematic without regard to parts
layout and lead dress depends entirely
on the project.
For "DC" projects, such as a
demonstration of an AND gate with
two switches, an LED, perhaps an IC,
a few resistors, and maybe a bypass
capacitor, parts layout isn't critical so
long as the bypass capacitor (from Vcc
to ground) is physically close to the
IC. It would even be okay to solder
component leads together with no
substructure or framework.
On the other hand, for radio frequency work (FM receivers, AM
receivers, garage door openers, etc.),
and for any project with a microprocessor, parts layout is critical, and
you should follow the perfboard
layout or printed circuit layout published with the schematic. If you don't,
stray inductance and capacitance can
wreak havoc with the circuit, and
unwanted oscillation may even occur.
In between are audio frequency
projects. For high impedance projects
— generally those with a low level
signal input — layout is critical.
However, for low impedance projects — such as a circuit to drive a
speaker from the output of an MP3
player — layout isn't critical.
#2 There are plenty of examples of
building circuits without a PC board
available on the net; http://blog.
makezine.com/tag/freeform/ is an
excellent example of this type of
freeform circuit building. It is
sometimes a little more complicated
than using a printed circuit board
pattern, but for some circuits, it's more
practical. As long as no leads touch
where they shouldn't and as long as
stray capacitance isn't an issue, the
circuits will function just fine.
80 September 2012
#3 Yes, you can wire parts together
in free air following the schematic and
in most cases, it will work just fine.
Indeed I have done just this on a
few occasions, either to lash up a very
simple circuit to test or for artistic
reasons. In general though, I would
recommend other techniques for day
to day use. Do some searching online
for electronic prototyping and building techniques; there are countless
methods that have been developed
over the years and you are sure to find
[#8121 - August 2012]
Cell Phone Amplifier
I need a parts list and schematic to
build a cell phone amplifier to
connect to standard headphones.
A LM386 based circuit would be
simple and will run from a 9V battery.
You can also buy a small kit such
as at www.electronics123.com/kits-
If the output sounds too harsh,
drop the gain by removing the
feedback cap (C1 in the diagram at
the first link).
[#7127 - July 2012]
RF Chip for Fuel Tank
Has anyone heard of a RF chip
which attaches to the fuel tank of a
vehicle and supposedly provides high
frequency output which increases fuel
While I haven't heard of the "RF
chip" you refer to, I have seen a great
many miracle gadgets over the years
claiming to increase your fuel economy. All of them, of course, come with
grand claims and glowing testimonials,
but invariably the only thing they do
well is extract money from your wallet.
There is only so much energy in a
gallon of fuel and modern engines do
very well at burning fuel efficiently
and extracting as much of that energy
as possible. The inherent inefficiency
in an internal combustion engine
comes mostly from the process of
turning heat into mechanical motion,
not inefficient creation of heat from
fuel. You can't argue with the laws of
[#8122 - August 2012]
Powering a Hydrogen Generator
I’m building a HHO generator and
am trying to figure out the best way to
power it, keeping the power usage low.
A high voltage, low amp method like
using a Tesla coil might do the trick.
Any ideas to help me figure it out?
First of all, try to avoid the term
"HHO" — it makes you look like a
crackpot. Electrolysis of water
produces a mixture of molecular
hydrogen (H2) and molecular Oxygen
(O2) in a 2:1 ratio. There is no such
thing as "HHO."
Second thing to know is that no
matter what you do, the energy into
the system is more than the energy
you get back out of the system. If you
put in one Joule of energy to break the
water into H2 and O2, you will get
back less than one Joule when the H2
and O2 is recombined. That's the laws
of thermodynamics and you can't
break those laws.
Now, what are you really trying to
do? You mention a Tesla coil but that
is a high voltage, low current system.
Electrolysis cells are intrinsically low
voltage, high current devices. To electrolyze water, you only need about
two volts per cell. Using higher voltages doesn't accomplish anything use-