Monday, October 11, 2010

BreadBoard Internal Connections

This article describes the internal connections for the BB300, BB400 and BB830 breadboards. 

A BPS (BusBoard Prototype Systems) customer asked us what the internal connections were on the BB300 breadboard.  I then realized that it isn't obvious to someone who is using breadboards for the first time how the internal connections are laid out.

The PDF datasheets for the BPS breadboards have now been updated with diagrams of the internal connections.

The datasheets can be found on the BPS web site:

Here are the internal connections for the BB300 breadboard with 300 connection points.  The BB300 has a circuit area with 30 columns of connections points on top and 30 columns below.  Each column has 5 electrically connected tie points.  Breadboards are designed so that a DIP integrated circuit spans the gap along the center line when it is plugged in.  Each IC pin then has it's own 5-hole column allowing wires or parts to be connected to it.

Here are the internal connections for a 400 connection point breadboard (the BB400).  The BB400 is a BB300 breadboard with distribution strips added to the top and bottom.  The breadboards are designed with interlocking clips so that they can be connected together to create a larger working area.
The distribution strips are usually used for power and ground.  When only a single voltage is needed for power, I like to use the red strips for +5 Volts and the blue strips for ground.  I connect the two red distribution strips with a wire and the two blue strips with a wire, so that easy connections to power and ground are available on the top and the lower areas.  A 100uF or larger capacitor should be added where the power comes into the breadboard, and a few 100nF capacitors added along the distribution rails to filter the power to your circuit.

If a distribution strip isn't needed for power, it can be used to carry some signal that is needed in several places in your circuit.

The BB830 and BB830T (T=transparent) breadboards have 630 connection points in the middle circuit area plus four distribution strips with 50 connection points each.
Note that some a few 830 connection point breadboard from other vendors have a break in the middle of the distribution strips that you need to bridge with a wire to get a strip running the whole width.

BPS breadboards are high-quality breadboards with clear silkscreen legends.  The contacts are rated for 50,000 insertions.  Each breadboard has double sided adhesive tape on back so the breadboard can be attached to a surface.  The BB830 and BB830T come with a metal back plate that can attached to the back if you aren't attaching the breadboard to a surface.

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