alan.melia at btinternet.com
Tue Nov 18 17:46:28 EST 2014
Yes below about 4v is the only place where you get the real "Zener" effect,
as you go above 5v it becomes Avalanche Breakdown. The trick is zener effect
has a negative tempco and avalanche a positive one (I think....they are
opposite senses anyway :-)) ) the result is a regulator diode
("zener"....so called) specced at around 5 to 5.5 volts has a near zero
----- Original Message -----
From: "Brooke Clarke" <brooke at pacific.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Tuesday, November 18, 2014 10:31 PM
Subject: Re: [time-nuts] 10811
> Hi Rick:
> When working on Tunnel Diode amplifiers we used (AFAICR) 5.1 V Zener
> diodes to stabilize the lower voltage that drive the diode.
> 5.1V was supposed to have excellent temperature characteristics in terms
> of repeatability (don't remember if low noise was part of the selection
> The boards with the terminals have the Zener and a custom compensation
> network using both Veco (spelling?) (-TC) and Balco (+TC) and fixed
> resistors so that the gain stays constant over mil temperature ranges.
> Mail_Attachment --
> Have Fun,
> Brooke Clarke
> Richard (Rick) Karlquist wrote:
>> On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote:
>>> I ground one side of the tuning diode and use the 2 to 12 V as the
>>> OCXO for my FRK's along with increasing the time constant. I have not
>>> verified it but I think removing the zener Voltage should also improve
>>> Bert Kehren
>> The choice for the Zener diode came from my old boss at HP,
>> who was very knowledgeable about using discrete zener diodes
>> as low noise references. According to him, this particular
>> part number has very respectable noise. This is just something
>> you have to know experientially, there is no theory of zener
>> noise AFAIK. You might try measuring the noise of the 6.2V
>> reference voltage directly at baseband, and then multiplying
>> by the 1 Hz/volt sensitivity. Let us know your results.
>> Rick Karlquist N6RK
>> (Now retired from HP/Agilent/Keysight)
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