One of my colleagues, Michael Dunn (editor-in-chief of Scope Junction), posted pictures of some of his favorite displays that have gone the way of the buggy whip. His article, “Grampa, Tell Me About Old Displays,” is a good read. But don't read it now — I have more interesting stuff here. I thought about sending him some pictures of some of my “antique” electronic devices, but he said I wasn't allowed to send him pictures of radio tubes. I insisted I would never publish picture of tubes merely as a cheap attempt to get people to pay attention to Planet Analog.
So, having set aside that concern, I found some devices in my junk box. These parts are now just old and in the way. They were purchased for projects once planned and then abandoned.
Down at the bottom of this page, you'll see a picture of some of my oddities. There's plenty more where these came from. For now, we'll just have a quick look at five pieces.
I had a surprising number of old diodes. One that is pretty typical was made by RCA and was part of a line of general purpose replacement devices it made. These devices usually had part numbers that started out with “SK.” The one shown is a Zener diode. The next device is a UJT (unijunction transistor) made by GE Semiconductor. UJTs could be used to make oscillators — they had properties that were unique — rather like a comparator combined with an SCR.
Next is a medium power SCR from Motorola, an SCR316-4 in a stud-mount package. The next part in the odd-looking dual-inline package is a small audio power amplifier. It has extra copper tabs sticking out of each side to help remove the heat. See below for an applications schematic for the TDA810, a functionally equivalent part.
Oh, and then there is that DSP from ADI. I don't quite recall the details for the device. I believe it had a Zerk® grease fitting so that special high-speed lubrication could be pumped in to help the device operate as fast as it did. I could be wrong about that.