In message , Martin Brown
writes
On 10/11/2020 03:22, wrote:
On Monday, 9 November 2020 18:31:29 UTC, charles wrote:
In article ,
Adrian wrote:
In message , Martin Brown
writes
That was the newer version after the one I described with the manually
assembled spring loaded clips and raw components. I suspect the base
board was the same on both kits. That sort of industrial hole board
that tools get hung up on. OK the transistors had longer flexible leads
them and some araldite reinforcement around the body.
You had transistors ?
I had (and still have) the Mullard book "Transistors for the Experimenter"
which was published in 1956! So yes, we had transistors in the 1950s.
way too expensive for kids' kits back then.
In the 50's yes, but by the mid to late 1960's there were even better
transistors about so that the OC7x, AC127 and AF116 were affordable.
ISTR blowing one up was still an expensive mistake for a schoolkid.
Memory lane.. For reasons best known to my employer, having shown no
specific aptitude and studying electrical engineering at college, I was
moved to the electronics dept. for my final 2 years as an apprentice.
I think the *whizz kids* who actually knew something had moved
elsewhere. The dept. had previously used Mullard Norbit gear but was
moving to an in house logic system using the Texas Instruments
germanium switching transistor 2G302.
Based on a *plug in* system using an 8 pin valve base and with timers,
delays, pulse units etc. it provided an easily repairable/adaptable
system. I got sent all over England and Wales doing the on site
commissioning.
TI discontinued production on the 2G302 and we changed to an equivalent
NKT218 from Newmarket Transistors. Also quickly discontinued so we had
to change the supply polarity and use silicon NPN.
--
Tim Lamb