Rich Measures wrote:
>Zeners are not adjustable. They usually don't survive a glitch. A
>string of foreward biased diodes is Way cheaper than a zener and they are
>adjustable in 0.7v steps.
This question keeps coming around, and whenever Rich mentions the string
of diodes, it's also the cue for me...
There's a circuit on my site that is continuously adjustable and gives
true constant-voltage regulation. This circuit uses the TL431
"adjustable zener" and a PNP Darlington boost transistor.
http://www.ifwtech.com/g3sek/boards/triode/triode-3.htm#4CathodeBias
Can't beat Rich's string of diodes for low cost, but the TL431 circuit
might still be cheaper than a very large zener.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
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