The model System 300 was introduced by Braun in 1969. It was both designed and the manual written by Mr. Joachim Schubert. The System 300 was also the second new complete stand alone product introduced by Braun, the first being the Buchlabor. The System 300 model was the Ausbausystem 3 with all the additional blocks necessary to complete the 100 experiments detailed in the accompanying A5 format 100 experiment instruction manual.

This model was focused on digital theory and computer techniques. Special blocks were designed and introduced for this model to represent a particular digital function. Flip Flop, NOT, OR, AND, Impedance Transformer, and Schmitt Trigger blocks were constructed using conventional transistors, capacitors, and resistors and featured larger sized blocks.

Oddly, integrated circuits were not used but rather analog components. ICs would be first introduced by Braun for the Demonstration 1300 model and it required a specialized 3.6VDC power supply to charge the nicad batteries used as the power source.

The System 300 layout in all its glory. This model was the second model (the other being the ausbausystem 3) which had the hinged cover. Both of these models reflected a new packaging approach (hinged cover) which was featured with the line of prototype models from 1968 which were sadly never productized.