Hi folks, I'm looking to identify what I think is a transistor, in a TO-72 package (TO-18 with four leads), in an old Victoreen radiation survey meter. The number is "ITS 30487". It's also marked "7736" which I assume is a date code.
Can anyone tell me what this is?
Thanks, -Dave
Probably an internal part number. BITD transistors were commonly marked with customer part numbers. (Around 1982, I was working in a group of RF engineers, and a lot of the parts available for us to use had cryptic part numbers like that.
I assume that one of the leads is connected to the case (the usual situation).
If it's the front end of a proportional counter, it might be a FET such as a 2N4117A JFET or a 3N163 MOSFET. For a Geiger counter, it would probably be something a bit more robust such as a 2N2222.
If none of the leads is connected to the case, it could be something less common, such as a dual-gate FET. I used to use a lot of 3N201s in that package.
Cheers
Phil Hobbs
I used to replace a lot of 40763 dual gate Field Effect transistors in garage door openers. I was doing the for a friend with a garage door business as a sideline. A nice part, but they didn't like nearby lightning strikes.
Hard to be sure, but Siliconix was making PFET junction FET discretes with that package, like this one
[archiveorg bitsavers_siliconixdixLowPowerDiscretesDataBook_42980376 width=560 height=384 frameborder=0 webkitallowfullscreen=true mozallowfullscreen=true]see page 120, 2N4867 series
If that's your item, pin 4 is the case (just a shield, not diode-connected to anything). There might be a S embossed on the can...
Coincidentally, I just bought a reel of BF998s, which are the last remaining dual-gate MOSFETs, now LTB, alas.
I don't use a whole lot of them, but the amount of design space I've been losing lately due to EOL parts is pissing me off.
The worst was the BFT92, which was almost ten times faster than the next fastest remaining PNP (5 GHz vs 600 MHz-ish).
Cheers
Phil Hobbs
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