Tr_XXXX

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THIS IS NOT THE NAME OF A TRANSISTOR TYPE

Manufacturers of equipment sometimes used designations such as:
* Green Spot
* White Spot 1, White Spot 3
* Blue Spot - or "Yellow Circle" (followed by a number) etc.

Such designations enabled the manufacturer to source from different suppliers and also to test the devices before assembly and code - usually with a coloured dot or ring.
This also aided hand assembly by the operators and inspection to ensure that correct devices were fitted.

This practice was mostly carried out during the early days of germanium transistor use when the quality and consistency of performance was frequently dubious.

 
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