The first version of the Mr. Wizard’s Experiments In Electronics model was introduced to the public in 1972 near after the acquisition of the Lectron System assets by Owens-Illinois that same year.
In addition to the 12 blocks, a 10K Ohm resistor was included to complete several experiments. Experiment #22’s completion required a 2nd earphone block which the manual suggested would be possible “… only if you have a friend who has an earphone which you may borrow“. The Electronics II model would correct this situation by adding a second earphone block.
34 experiments could be explored with the included Mr. Wizard instruction manual. This was the only item that was not ‘reused’ from the Raytheon product line but was rather created specifically for the Mr. Wizard series (to match the ‘look’ of the Mr. Wizard instruction manuals for the other three, later four, product lines).
The Electronics (I) model’s instruction manual (on page 5) was the only one which provided even a passing acknowledgement to the source of the Lectron System (at the time) Braun AG. At least the manual did not attribute the Lectron System’s origin to Raytheon!
The complete instruction manual may be viewed/downloaded from the Kimble documentation page.