science project

Small triacs were only a dollar or two ca. 1970. For example, check out Don Lancaster's "Color Organ" from '69:

The whole power board kit with three RCA triacs c/w integral heatsink, including a couple of RTL logic chips, was less than $14 including postage.

Don's earlier version (1966) used SCRs:

Perhaps interestingly, about the only electronics components in those designs that are not obsolete are the 1N400x series rectifier diodes.

On a sunny day (Fri, 18 Dec 2009 14:32:38 -0800) it happened Joerg wrote in :

policy

In the end of the sixties I changed jobs, and had the responsibility for keeping many million dollars of equipment running. No design for a while :-) I never worried about the price of electronic parts... made plenty of money.

Long before that, at school I made some money selling electronics. As a little kid, what electronics I could not buy I would borrow or steel...

On a sunny day (Fri, 18 Dec 2009 17:41:05 -0500) it happened Spehro Pefhany wrote in :

Now that is nice, we do not need no opamps :-)

SCRs we could always buy. Triacs, very different story. You have to keep in mind that this was in Europe. When my father came back from a biz trip to the US in the early 70's he brought me some magazines and there I was all drooling. The prices you guys got were amazing. Heck, a lone SN7490 cost us kids over four Deutschmarks so I decided my frequency counter had to be cut to six digits and later be expanded to eight when more money was saved up.

It was not much better in the Netherlands where Jan lives because I shopped there a lot. The reason we went was not new parts because they often cost even more there. But they had excellent "dump handelaars" that sold old surplus stuff at much better prices than the German surplus dealers. The was the real source of parts.

You can still get a 0.022uF cap. Except it might be called 22nF in modern speak :-)

I haven't used opamps much until I was twenty-something and I am very glad for that. You wouldn't believe how many younger engineers are hardly able to do anything on the transistor level these days. Sometimes when explaining a ciruit I have to start pretty much at Adam and Eve ;-)

Among very young ones I even encountered some to whom even opamps where quite foreign. But they were excellent uC programmers. Classical scenario ... "Oh, we need a bigger DSP if we want to do that" ... No, we don't need any processor to do that" ... "HUH?"

It wasn't too much later. I built a scoreboard for my nephews' hockey team in the early '70s using triacs as seven-segment drivers (60W bulbs for each segment). Triacs were well less than a buck in a piece in tens sorts of quantities then.

In Europe that took a while longer. I remember that I sometimes inquired back in the 70's but mostly resorted to the old trick, a bridge rectifier and a transistor or SCR. That was also good for some PWM without screwing up the power factor too much. Not that anybody cared about PFC back then but classic triac dimmers cause a lot of annoying buzz.

message=20

from

an=20

He has been around but the basic patent is:

\u201cSemiconductor Switch\u201d.

Even i was a teen by then.

in message=20

from

might

make an=20

:-)

You must have been shopping different places than me. I had bought my = own=20 triac based dimmer by 1968, while still in high school. I think about $4= at=20 the time, i had to scrimp for a month. I still have it and it still = works.

inside=20

One of their big drawbacks in acceptance was 3-way lamps. Now with=20 incandescent going away (slowly) triac dimmable lamps are becoming an = issue.

message=20

from

an=20

Actually they would "visit" the parents, and only if and when they found = out.

message

I lived in Europe and anything electronic over there still had early adopter price tags while over here it was probably on the regular shelves at places like Sears. I still remember when my father brought the first pocket calculator back from a trip to the US. We might very well have been the first family in town who owned one, sitting around the table and marveling at that little thing.

message

When a kid lasered a helicopter out here the pilot must have called in the location with such precision that the sheriff was there almost immediately.

Youngster!

When I hear Joseph, or you, or others and then look at my own age I begin to think that this and a lot of other newsgroups will be pretty much gone 20-30 years from now ...

message

Same here in AZ. A kid in Mesa was lasering flights in and out of Sky Harbor. He had done only around six when DPS drove right up to his house. ...Jim Thompson

Joerg Inscribed thus:

True ! We're getting closer to the front of the book. ;-)

JosephKK Inscribed thus:

I made a touch sensitive light switch around that time with one.