![Noise](photo_cgs96_comp.jpg)
Triple Comparator
for music synthesizers.
SUPERSEDED BY CGS596
The Triple Comparator consists of three independent functions which are useful in the production of square waves and variable pulse
waves. The Comparator reference level can be a time-varying control voltage, a
complex audio signal, or a fixed preset voltage. Additionally, the comparators are
useful for level detection and for logic decisions based on amplitude. The module
also contains a single, non-adjustable, Schmitt trigger.When running from +12 volts, the output of the Schmitt
trigger will rise to about 5 volts when the input falls below approximately 0.6
volts and will fall to approximately 0 volts when the input rises over
approximately 4.3 volts. This section of the module is frequently left off
panels
It will work on either +/- 12 volts, or +/-15 volts. No negative power rail is used.
A little on how it works:
The schematic for the Triple Comparator
The upper part of the diagram
shows the Schmitt Trigger, while below that are three identical
comparators.
At the very bottom is the local "6 volt" regulator. (This will
supply a higher voltage when the module is run from 15V, unless the values
of R2 and R3 are swapped.)
Construction
Note: On the
VER1.0 PCB, do not use the 0V pad. Instead use either the CCW end pad of the pots
or the spare pad at the edge of the PCB next to R3
![](photo_cgs96_comp_rear.jpg)
The lower photograph shows the position sof the three 100mF SMT capacitors
|
Pad identification |
![Wiring](wire_cgs96_comp.jpg) |
A |
Comp 1 Input 2 (+) |
B |
Comp 1 Input 1 (-) |
C |
Comp 1 Output |
CL |
Comp 1 LED anode |
D |
Comp 3 Input 2 (+) |
E |
Comp 3 Input 1 (-) |
F |
Comp 3 Output |
FL |
Comp 3 LED anode |
G |
Comp 2 Input 2 (+) |
H |
Comp 2 Input 1 (+) |
I |
Comp 2 Output |
IL |
Comp 2 LED anode |
B POT |
Comp 1 pot CCW (0V), Wiper, CW (+6V) |
E POT |
Comp 2 pot CCW (0V), Wiper, CW (+6V) |
H POT |
Comp 3 pot CCW (0V), Wiper, CW (+6V) |
0V |
NOT USED on
VER1.0 PCB |
+6V |
Local +6V (Not used) |
|
Part
Identification |
R2 |
5k6 for +12 V power supply,
6k8 for +15 volt power supply |
R3 |
6k8 for +12 V power supply,
5k6 for +15 volt power supply |
Set up:
Connect a bipolar triangle wave (i.e. AC coupled, or having equal swing above and below 0V) into the B input. Set the top (B) pot fully counterclockwise. Adjust the trimmer for a 50% dutycycle output. Use a scope, if you have one, or set the speed of the triangle wave low enough that you can use the LED to monitor the output
Notes:
- The module will work on +/-12 volts.
- PCB info: 6" x 1" with 3mm mounting holes 0.15" in from the edges.
Parts list
This is a guide only. Parts needed will vary with individual constructor's needs.
Article, art & design copyright by Ken Stone |