CGS breadboard

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PCB used with 4 pin power connector.
PCB used with 6 pin power connector.

CGS124 is the CGS breadboard a module prototyping PCB.


The component overlay for the VER1.0 PCB. Click through for an enlarged, printable version. Print at 300dpi.

Color legend (assuming +/-15 volts).

  • Red: +15 volts
  • Green: 0 volts/ground
  • Pink: +5 volts. Note that pin 16 of the SO-16 is preconnected to the +5 bus.
  • Orange: Free bus. Use it for clock signals or something else that you wish to distribute along the length of the PCB.
  • Blue: -15 volts
Pad 16 of the SO-16 location is pre-connected to +5V, suitable for logic chips. If you wish to use a quad op-amp or other 14 pin linear device, mount it to the left, so pad 16 is not used. To isolate pad 16 from +5V, carefully drill out this hole. You only need to isolate the through-hole plating from the pad. It can be done on either side. A simple twist of a 1.5mm drill bit held between your fingers is enough to do the job. Check for continuity to made sure you have succeeded. Take care not to cut any of the traces connected to the pad by over-drilling. Click through for an enlarged version.

The board can be used with either +/-12 volts or +/-15 volts, although the power connectors used are usually associated with +/15 volts.

On the rear of the PCB are various surface mount pads. These are to allow connection to the rails and IC pins under the SMT packages. There are also four pads associated with decoupling capacitors, allowing 1206 SMT decoupling capacitors to be used in these locations.

There are several power supply configurations possible with the board. Of note is the two variants of +5.

  • If you have a power bus that uses the MOTM standard for +/-15/+5, you can install a six pin 0.156 header, three Ferrite beads and three 10uF decoupling capacitors.
  • If you only have +/-12 volt or +/-15 volt power available, install a four pin 0.156 header, two Ferrite beads, two 10uF decoupling capacitors, two 100n capacitors and a 78M05 (or similar) regulator. Refer to the photographs for component positioning.

Parts list

This is a guide only. Parts needed will vary with individual constructor's needs.

Full module using 4 pin power
Part Quantity
100nF (=0.1uF) Ceramic Monolithic 8
10uF electrolytic 2
78M05 or sim. 1
Ferrite bead 2
MTA-156 connector 4 pin 1
MTA-156 header 4 pin 1
CGS124 VER1.0 PCB 1
PCB used with 6 pin power
Part Quantity
100nF (=0.1uF) Ceramic Monolithic 6
10uF electrolytic 3
Ferrite bead 3
MTA-156 connector 6 pin 1
MTA-156 header 6 pin 1
CGS124 VER1.0 PCB 1


  • 330R refers to 330 ohms. 100n = 0.1 uF, etc.
  • The module will work on +/-12 volts or +/-15 volts.
  • PCB dimensions are 6" x 2" (152.40 mm x 50.8 mm) with 3mm mounting holes 0.15" in from the edges.


Readers are permitted to construct these circuits for their own personal use only. Ken Stone retains all rights to his work.

See also


External links