My CK722 Transistor

I’ve acquired an old Ratheon CK722 transistor several years ago. I knew it was a find when I got it, but then it sat, stored away, for many years.  Today I took some pictures of it and here they are.  If you have never seen one of these beauties, they are royal blue with a red dot on them.  It has a date code on it that says “542”  That means it was built in 1955 in the 42nd week.

The inside of the package has the strangest disclaimer.  It reads “The purchaser or lesee of this device shall not be granted by implication, estoppal or otherwise any license under the patent rightsof American Telephoneand Telegraph Company andits subsidiaries for any combination of another element orelements with such device.”

The CK722 started out costing more than $12.00 to purchase and later went down to $7.50.  WOW!  I have no idea what that is at the current rate, but it is expensive.  I could not find the current price of one of these gems.

Click a picture to see a larger view.


The Beautiful Blue Raytheon CK722 Transistor. Package Front Package Back The Inside Of The Package. A Very Interesting Disclaimer.

3 thoughts on “My CK722 Transistor”

  1. Thankyou for this trip down memory lane. This is the first transistor that I ever bought, the “see-kay-seven-two-two” and other than the 2n3904 and 2n3?55 its the only part number I recall. I’ve used hundreds of 2n3904s and 3906s during my lifetime.

    73, Rod VA3ROD

  2. I purchased some of these in the middle 1950s. I paid only a dollar a piece for them from a military surpluse store in Hessville or Hamond Indiana. Still, a dollar in those days was quite a bit. I think I still have a few of them laying around somewhere.

    Bill N9JTR

  3. I have a few of these, including one of the original black with glass base models, a beautiful second generation blue one, and an older third generation silver one. They’re worth anywhere from $10-$30, depending on the rarity and condition, in spite of what people are trying to get for them on eBay. The black ones are the rarest, which I believe I paid around $20 for. The others I grabbed for $10. Add a few dollars if they still have their original packaging, and subtract a few dollars if they have clipped or obviously wire-wrapped leads.

    There really is zero demand for them beyond collectors, and there probably aren’t too many of us who are passionate about early germanium transistors. 😉 It looks like you have a nice example, which I would value at between $15-$20. If I ever get around to picking up a few more, I’m considering making a small transmitter with them…

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