$161 oscilloscope

You didn't have a spare inverter section available?

Cheers

Phil Hobbs

On a sunny day (Sat, 18 Dec 2021 14:27:17 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

My first transistor was the OC13 (Philips) Ge PNP 10mA LF

It was a military job and we were supposed to use JAN-TX silicon transistors. I wrote an elaborate bit of nonsense why we had to use a commercial part (raving about capacitances and stuff) and we got away with it, out of frankly stated admiration for my BS skills.

Mine was prettier, a really nice translucent purple-blue paint on an aluminum can. Inside was a smaller hearing-aid transistor in a can, a reject from the main batches.

On a sunny day (Sun, 19 Dec 2021 08:24:57 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

Yes, but if you removed the paint from mine, then you could use it as photo transistor. It actually gave of some voltage when in the sun.

I used to use selenium solar cells as photoreceivers. A flashlight bulb and a selenium-cell receiver made a surprisingly good audio link.

I wonder what the selenium efficiency was. 1% ?

I also used a Ge transistor in a flashlight reflector as a thermal IR detector. It could detect my hand from a foot or two away.

On a sunny day (Sun, 19 Dec 2021 09:40:29 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

Googing (it that knows [almost] everything) for 'selenium solar cell efficiency' gives scholar articles, 5.7%.

Nice, did you just measure output of the transistor or use it in some powered circuit with gain? I still have some OC71 (I think it is) here that I took from old army equipment.

It has been a while. I think I put it in series with a battery and a pot and a mA meter and ran it partly into thermal runaway, which greatly increased the sensitivity.

I did a lot of crazy stuff as a kid. Flashtube/PMT lidar. Poisonous HV Kerr cells. Thyratrons dumping caps into auto ignition coils. Filament-controlled HV rectifiers on neon sign transformers charging big oil caps. Giant electrolytic cap bank magnetizers. Radioactive stuff. All kinds of fun dangerous things.

I think the first one I bought was a TR01-C, a TO3-packaged germanium made by IR. (I think it was germanium, anyway, but I was 11 years old, so I don't suppose I had any idea of the distinction.) I haven't been able to pull up a datasheet on it.

Cheers

Phil Hobbs

NTE calls this an equivalent - probably close enough:

On a sunny day (Sun, 19 Dec 2021 12:50:37 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

I may scrape the paint of an OC71 and see if it sees me in IR..

Yea, I remeber having a big round TV CRT with HV generated by an audio amp feeding into a car ignition coil, on my bed. That was also the horizontal scan IIRC. And then an other audio amp on the vertical deflection coils. My oscilloscope! No sync... Dangerous, implosion danger. In my last year at highschool I tried donating it to our physics teacher, but he did not want it (should have made a nice display in the auditorium) maybe he was afraid of it?, so the tube went back to the local TV repair shop where I got it from. BIG scope! Before that all sort of RF transmitters, even one with transistors, had our own radio FM station in the basement. :-) Before that 1.5 V tubes. Before that crystal radios.. Now we are in the early fifties. Chemicals? I build some thing that increased pressure in some can, and put it under the teahers desk, the lid went boom after a while. The danger was not much in the boom but in me being kicked out of school... Not that I gave a dime in those years, parents then send me to a boarding school... You shall study. Rebellion?

Sinatra 'I did it my way'

Mine came in the Philips EE-20 kit produced "63-65?" which would make me around 9. I still have a few of the parts, sad to say. (Yes, the rest of my house is as that implies, compounded by being in the middle of clearing my parents' house)

The manual was remarkably good: - top half explained circuit theory - bottom half explained construction techniques

Hans Otten seems to have a pleasing fetish for the Philips EE kits :)

Kids are so much more protected now, and so much more afraid.

It shows that the average age in this group is over 60.

The irony is that the old line is getting old enough that they are fading away and the average age is probably getting younger now. After all, none of us keep getting older indefinitely.

Looks about right, thanks. It was a megaphone project from a book--used a carbon mic button, a speaker, and +-3V from four AA cells.

Worked fine but really chewed batteries.

Cheers

Phil Hobbs

You just reminded me of one of mine. I thought it would be so cool and impress my 7th grade science teacher, Mr Ragle, by bringing in a big bottle of hydrogen. I just read about electrolysis of water (I used an electric train DC power supply -- that had a 'smelly' Selenium plate dual-diode; and carbon rods from "D" cells). He was cool as a cuke, "that's nice", & gave it not much concern. You see, the bottle was plastic (shampoo), sealed with a work & some wax. So unbeknownst to me, the danger leaked out way before I even got to school. He was kind & didnt "leak" this information to me, though.

well to be fair, some parents (mine) had no clue we were doing these risky things in the basement... (not that it would've made much difference, in my case). Although, once I blew out a fuse, & darkened some rooms (shorting out the AC line - I though carbon had more resistance than that...), that get their attention.

The early power geraniums were much worse. I guess it's hard to move back & forth under the weight of all those stems.