Diode numbers

Cliff Jones wrote:

youbetcha, I'm saving that one as an mht file on my computer and will edit it and make it into a pdf file.

Great minds think alike Cliff. Been doing that for ages myself.

youbetcha, I'm saving that one as an mht file on my computer and will edit it and make it into a pdf file.

Cliff Jones wrote:

Heres a link for transistor History with lotsa Pictures:

Click Here for Transistor History

Haven't seen that link before. Neat site, thanks Cliff.

Bob

Heres a link for transistor History with lotsa Pictures:

Click Here for Transistor History

I just read in a naval manual that the designation numbers on signal diodes such as 1N21 mean the last number 1 relates to the maximum frequency it can detect. So the 1 means 1cm. Interesting to know.

information on transistors and crystal diodes, detectors.

Here's a bit I posted on TRF.
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This Sounds better than the selenium type. I know they were used in older meter movements.
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Copper Oxide Rectifier

With the use of the copper oxide rectifier in a recent receiver of the portable type, their popularity will possibly be revived for radio purposes, as in the days when they supplied rectified a-c for the fields of loudspeakers.

Any device which offers a high resistance to the flow of current though it in one direction, and a comparatively low resistance to the flow of current to it in the opposite direction, makes a good rectifier for an alternating voltage. This is the case of the dry contact rectifiers, such as the copper oxide type. The copper oxide rectifier is made in the form of a copper disk, coated on one side by a layer of copper oxide. The copper oxide is plated with nickel to allow good external circuit contact. The juncture of the oxide and copper offers a low resistance to the flow of current from the oxide to the copper, but a high resistance to the flow of current in the reverse direction. The detailed operation of this device is complex, but in general it involves the formation of thin films at the junction of the oxide and copper in which the molecules are so polarized that the transfer of electrons in one direction requires much less work than a similar transfer in the opposite direction.

Copper oxide rectifiers possess a definite breakdown voltage and breakdown temperature. If either critical value is exceeded, the rectifier will pass current freely in both directions. After the unit is cooled or the high voltage removed, it will immediately function again as though it had not been overloaded.

The copper oxide rectifier can be connected in either the half-wave rectifier or full-wave rectifier circuit.

The test for proper single disk operation is to impress a ½ -volt d-c across the disk in the conducting direction; then the current should read should read 0.5 amperes or more. By reversing the battery polarity a current of no more than 2 ½ Milliamperes should flow when 2 volts is applied to the disk in the non-conducting direction.

This was copied from the General Electric Company Electronics Department, booklet #175-3012A THE ABC's of RADIO (copyright-1943).