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Diac's Again

There aren't as many manufacturers. Try Teccor, which makes DIACs in the DO-35 (small signal axial diode package) as well as DO-214 (surface mount). One distributor is Digi-Key; another is Mouser (they only stock the thru-hole parts).

DIACs were made primarily for analog phase control of AC loads using an RC charging circuit. That's nowhere near as amazing as it was in the '60s, when these parts were developed. The simple phase control circuit (view in fixed font or M$ Notepad):

___ o -|___|--o--------------. Load | | | | ..-. | | |

Reply to
Chris
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I have several general questions on Diac's.

It seems that some electronic places dont sell Diac's . I went to one place that I buy parts from and they said they dont sell them. Another place didnt have them out on the shelf for me to look at but I had to have a part number. The sales person was somewhat unfamiler with them. Are diac's little used ? It also seems that there are a relatively small number of Diacs NTE I think has about 4 that I can see. I'm just wondering if anyone knows why the Diac seems to be so maginalized.

Some web sites list them as "Bidirectional Diode Thyristors". At least I asume thats a Diac. eg. It is in the Thyristor family, it is two diodes oposite each other and it is bidirectional.

Thanks

Reply to
Trudeau

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Thanks Chris,

I have read some tutorials and lessons on line regarding Diac's. And will read the little fuse faq. I just sort of thought that Diacs would be a usefull thing. in reducing stray low voltages. Admintedly the circuit has to withstand the dam bursing when it suddely conducts but it just seemed like usefull tool and simple. I wanted one that had a breakover voltage of about

20volts but virtually they all start at about 28. I probably wount buy it because I'm not going to mail order one part for 2 bucks.

Thanks again for the usefull info.

Reply to
Trudeau

Trudeau schrieb:

Hi,

Diacs are mostly used with Thyristors or Triacs to control a lamp (so called Dimmer).

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The better Technology is to always switch power at zero crossing of mains voltage and to feed the power while whole periods to the lamp. For this purpose there are IC's to control the Thyristor/Triac.

Because Diacs are used in a such special application, the market is small and not so many manufacturer and types.

HtH RW

Reply to
Rudolf Wiesendanger

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