| No. |
|
Circuit Image |
|
Circuit Description |
| 1 |
|
90-watt
RMS Audio Power Amplifier |
|
A Quasi-complimentary
power-output stage for an audio amplifier that delivers about 90-watts
RMS into 4 ohms before clipping. Uses an all-NPN final stage and a single-ended
supply. Note: This is an experimental design that is not intended for
practical use. |
| 2 |
|
Low-power
FM Wireless Microphone |
|
Small, wireless microphone
that will transmit a whisper to a nearby (1/4 mile radius) FM radio, tuned
to the 100 - 108 Mhz region of the dial. Powered by 9-volt battery, and
features hand-wound inductor. This Detailed
Description contains theory of operation, construction tips, and some
testing procedures. |
| 3 |
|
Guitar
"wah-wah" Effect |
|
A fairly high-Q bandpass
filter design with cutoff frequency controlled by a foot-operated potientiometer.
The poles of the filter are designed for the guitar spectrum. Single-supply
operation and low-noise make it a cool toy. |
| 4 |
|
High-Q,
60-Hertz Notch Filter |
|
very high-Q and narrow notchband,
make this a cool experiment in active filters or in Real Life to remove
some nasty noise from that vintage guitar. |
| 5 |
|
Three-band,
Active Tone Control |
|
Provides Bass, Midrange
and Treble boost and cut. Single-supply operation. |
| 6 |
|
Phase
Shifter |
|
The classic, swishy sound
of the 70s and 80s is coming back. Be ready with this interesting effect.
Provides 0 to 180 degrees of phase shift, with a variable sweep control.
Works for keyboards and guitar. |
| 7 |
|
Monitor
Saver |
|
A simple device that connects
to an unused parallel port on your PC, and coupled with a Simple
Device Driver, powers down your monitor during periods of system inactivity,
saving both energy and your monitor. |
| 8 |
|
Transformerless
Power Supply |
|
An interesting application
of capacitive reactance, which is used to reduce the normal, 117-volt supply
to 12-volts DC, regulated, delivering about 100 ma.
NOTE:
This circuit must be used with caution, since it does not provide the normal
isolation achieved with a standard transformer design. With careful construction,
however, it can be used in a variety of small, low-power, solid-state applications. |
| 9 |
|
Parallel-port
Debugging Aid |
|
A useful device which can
be built (if you're patient enouch )into the shell of a DB-25 connector.
It provides simple visual indication of 8-bits of data useing LEDs and
provides three inputs, via switches. Plug it into a parallel port on your
PC and then imbed special instructions in your code to provide visual feedback,
simliar to a "PORT 80" card. |
| 10 |
|
PracticeMan(TM) |
|
An experimental
device intended to be used as a self-contained musican's tool. Has built-in
clean, and overdriven preamps, three-band, active tone control, and auxiliary
outputs to feed your standard amp. |
| 11 |
|
One-transistor
Regenerative AM Receiver |
|
A classic design revamped
slightly. Features a single-transistor regen stage, and a range of 1000
miles with a 4-foot antenna. Perhaps the best "survival radio", yet. Now
updated with speaker amplifier. |
| 12 |
|
Electronic
Roulette Wheel |
|
A novel circuit that duplicates
the function of a 10-slot Casino-style Roulette Wheel. Features a "coast-down"
clock generator, to add realism. |
| 13 |
|
68-Watt
Power Amplifier |
|
Experimential power amplifier
using the low-cost LM3886 monolithic power amp IC. Suitable for sound reinforcement
in small to mid-sized clubs. Includes parts and circuit for 28Vdc bipolar
power supply. |
| 14 |
|
Charge
Pump Voltage Quadrupler |
|
Simple circuit that will
quadruple an input voltage. Useful for bias supplies and programming voltages. |
| 15 |
|
Telephone
Recording Switch |
|
Switches on a Tape Recorder
and records both sides of the conversation, when a phone is picked up.
Useful to log all telephone conversations. |
| 16 |
|
Guitar
"Direct Box" |
|
Hang this on your Fender
Twin or other guitar amp and feed your sound directly into a mixing board
or PA. |
| 17 |
|
Binaural
Microphone System
|
|
A low-cost, hi-fi binaural
mic setup for unencumbered recording of stereo sound, typically with the
new Minidisc recorders. |
| 18 |
|
Basic
Electric Guitar pickup configuration. |
|
Very basic two-pickup configuration
for electric guitar, with volume and tone controls. |
| 19 |
|
Leslie
Speaker controller |
|
Very basic but viable Leslie
Speaker controller. Includes noise-abatement components, to ensure
smooth, quiet Tremelo/Chorale transistions. |
| 20 |
|
Temporal
Power Supply |
|
A novel battery-operated
power supply that provides a finite period of power, controlled initially
by a pushbutton (or other SPST/NO switch), and subsequently by the controlled
circuit. This lets battery-operated devices turn themselves off after
a period of inactivity. |
Unless noted otherwise,
all circuits, graphic images, and text copyright © 1982-2001,Len
Galasso All Rights Reserved.
No commercial applications,
without written permission.
Updated 5/10/2001
"Watch your back, JD."
