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Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
Why not use a triac so you can get the full 0-100% wave? With a SCR, you get 0-50% because like you mentioned, the SCR blocks the current in the other way.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
Myke wrote ... Why not use a triac so you can get the full 0-100% wave? With a SCR, you get 0-50% because like you mentioned, the SCR blocks the current in the other way.
Agreed, for little stuff like light dimmers. For really big stuff, triacs aren't made, so one uses two or more SCR's.
Registered Member #2628
Joined: Fri Jan 15 2010, 12:23AM
Location:
Posts: 627
Well, I do have both SCRs and power TRIACs, I just like to use SCRs over triacs, since I have so many of em, and they are usually higher powered anyway. in the picture, the SCR is the ratings radiotech has said, 400V 25A. while the traic is the same amperage ratings, so just for the sake of simplicity, Ive desided to use SCRs.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
If you connect the anode of the SCR to the + terminal of a bridge rectifier and the cathode to the - terminal you can connect an AC load in series with the input to the bridge. This will act like a triac, handy for big loads.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
I have some prototype 741 Metal can ICs. Some old metal can transistors too. That's about it.
Oh yeah i have some vacuum glass encapsulated victoreen resistors.
I Love old parts! Whoever doesn't want them, give them to me! I've always wanted a metal can 555 timer. I've also always wanted to build an all-glass circuit. (Glass resistors, tubes, reed switches, selenium rectifiers, neon lamps...)
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
Some of the first transistors were glass-found in British & German radios made in the 50's. They were painted black-Mullard-Philips-Telefunken- alloyed junction prefix OC. If paint flaked off light got in and made them phototransistors-so we painted them again.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
radiotech wrote ...
Some of the first transistors were glass-found in British & German radios made in the 50's. They were painted black-Mullard-Philips-Telefunken- alloyed junction prefix OC. If paint flaked off light got in and made them phototransistors-so we painted them again.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
I shall look for one for you meanwhile go here:
finding replacements for audio gear is hard. i found Wireless World May 1965 here and they are for sale in that -- see here-- damn no scanner here ! back in the era ! found a 1958 Popular Electronics
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old parts?
