The color specifies the transistor gain H fe: Brown 35-70 Red 55-110 Orange 90-180 Yellow 150-300 Green 235-470. The 2N2926 with its dot of paint is such an unusual transistor that it had to be that, even with a different markingįigure 1: 2N2926 transistors. I confirmed that the gains of my transistors corresponded to those shown in the table, and that sealed the deal. The 2N2926 ( Figure 1 ) is a strange-looking transistor, and it had to be the same, even though mine were not marked as such. There was the 2N2926, with the same case, with a note that the dot of paint on top of the case showed the gain range. Success came when by chance I saw a table of transistor data in the Practical Electronics magazine I got at the time. So, identifying the actual type number of these transistors was a challenge. I did know that transistors marked “Bxxx” were often from the Japanese 2SB series, but when I referred to my copy of the venerable Towers International Transistor Selector book, the 2SB686 was a PNP power transistor and mine were NPN signal types. Now, in those days, the Internet didn’t exist, and data books were rare and expensive. However, they were marked “B686” and had a dot of paint - brown, red, orange, yellow or green - in a dent on top of the case. The transistors were in a very weird package, but with a simple transistor tester I built from an article in a magazine, I identified them as NPN types.
Components were expensive and not always easy to get, so these boards were gold for me. However, this was in Zimbabwe (then Rhodesia), which was not the centre of the electronics universe. They had the leads bent over on the underside of the board and even the large soldering gun my dad also got for me had problems removing some components.
The boards contained transistors, resistors, diodes and a few capacitors. I got interested in electronics in my early teens - about 50 years ago - and my father, who was in sales at an accounting machine firm, got me scrap boards from the techs there. Many readers will, like me, be hobbyists who scrounge parts off old electronic equipment. However, it is not always easy to determine what is what. Developing your component identification skills also enables you to create a stock of spare parts that might come in handy someday. Being able to identify the parts on a circuit board is primordial for repairing it.
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