Binary Full-Adder Model
או in Hebrew is OR, גם is AND, and לא is NOT
(The only pictures left, which I have received from the WIS PR)
This working model was built in 1964 during the summer vacation (together with sailing and instructing at the Haifa Sea Scouts, and helping in Construction to finance my Electronics hobby), after completing my 11th grade at high-school (Leo Baeck, Haifa). Just before the vacation my Physics teacher, Meir Salmon, handed me a brochure of the 1964 Annual Modeling and Inventions Competition by the Weizmann Institute of Science (WIS). I decided to build a computer component for the competition, the "summation unit" (I learned the term "full-adder" years later). The model was inspired by a series of articles named "The electronic brain" about digital computer internals. It appeared in the monthly professional magazine Radio and Electronics (in Hebrew) which I have subscribed to before and during my high-school years. I designed and built it myself with no mentor or adviser. Some components I got at the "Junk," a warehouse for surplus used military electronics (only years later I learned the meaning of "junk"), and some components I built myself. I worked on it a substantial portion of my summer vacation.
The model had arbitrary inputs (by on/off switches) and memory for carry and result. This information and gates' states were displayed on a logic circuit diagram with small light-bulbs (on/off) for each computation cycle. Gates were built each individually.
The model won the second prize in the WIS competition . My entire high-school was invited to visit WIS and to attend the award ceremony. The 11th and 12th grade classes participated in the journey, which included also visiting the Golem computer project at the institute. Golem I started operating in the same year, 1964. Golem II later in 1972. The project leaders were my examiners. Computers emerged and have become a subject of curiosity. All three top prizes were awarded for computer related projects. By 1964 a total of 1400 first and second-generation computers (pre System/360 series, which started shipping in 1965) was the entire digital computer installed base of IBM world wide (besides a large base of other data processing equipment).
Portable Regenerative MW Radio (1960)
Most radio sets have been large, radio-tube (vacuum-tube) based (no TV sets at that time in Israel; public TV broadcasts started later in 1968, and radio sets were a main entertainment and information source). Portable Transistor radios started to appear, and I wanted one... They later became a craze similar to today's iPhone. They were quite expensive in 1960, about $400 in today's currency, which was a fortune in
Israel at that time. The first commercial one was introduced in the US in
May 1954. In the summer after the seventh grade I have found a relatively simple circuit diagram for such in a magazine, and worked many days at an electrician's shop repairing burnt irons and malfunctioning lamps to have money for the needed components. The RF components needed to be aligned in certain positions to avoid mutual interferences. Later I also built a small, portable, low-power MW transmitter (military walkie-talkie like). It was not very selective, broadcast on a wide band, and probably drove the radio sets in the neighborhood (and the neighbors) crazy. It was stolen and disappeared...
I read about, and built my first Crystal radio when in the fourth grade (1956). When dealing with my long wire antennas (10-20 meters) on the roof I met two new neighbors who shared a rented room, EE students and amateur radio enthusiasts. They erected a "strange-looking" antenna. Since then I have spent time with them in their in-room lab and radio station when possible. I also attended a first level (lowest) amateur radio course. Later I got electrocuted when messing with radio tubes (luckily getting shot two meters away, rather than "glued" to the device), and moved completely to the new, safe, low-voltage transistors.