[time-nuts] Supply voltages for the Efratom 105243 10MHz OCXO

[Greg Broburg]

Great idea.

Greg

On 3/20/2011 10:02 AM, Ed Palmer wrote:
> Measure the wattage used by the heater at 24V and room temperature.  
> This is what's required to keep the oven at the proper temperature.  
> Lower the voltage to 20V and see if the heater draws the same 
> wattage.  As a second check, measure the current drawn at 20V at 
> startup and then after warmup.  The difference tells you how much 
> headroom you've got until the heater runs full on.
>
> Ed
>
> Mike Millen wrote:
>> Many thanks to both of you.
>>
>> Is it safe to assume that the oven has its own temperature control 
>> system?
>> I ask, because I'd prefer to run it from  approx. 20v instead of 24v.
>>
>> With a controller (& a room-temperature environment) I'm hoping that 
>> it would still be
>> operating at its design temperature with a lower voltage.
>>
>> Comments?
>>
>> Mike
>>
>>
>> Bob Camp wrote:
>>>
>>> The board looks a lot like a pull from a Lucent base station. The
>>> voltages would all make sense in that context. The unit swaps in for
>>> an LPRO and the 15V would be easy enough to come up with. I'd bet
>>> they ran both pins off of +24 though.
>>>
>>> Bob
>>>
>>> On Mar 19, 2011, at 5:20 PM, Arthur Dent wrote:
>>>
>>>> The pinout shown is close. The oscillator supply voltage on the
>>>> one I have in circuit is +15 @ low current. The Oven requires
>>>> 24VDC @ .25A and this drops to under 100ma when the unit
>>>> reaches operating temperature. There apparently is an internal
>>>> regulator on the oscillator supply and if you watch the output
>>>> level as you increase the oscillator supply voltage you will see
>>>> it increase until you hit about 13.5VDC then it remains constant.
>>>> This may mean that you could run the oscillator on either 15 or
>>>> 24 volts but where I'm only guessing what's inside the case I'd
>>>> stick with 15VDC to play it safe. The pin next to the output that
>>>> goes through the on board  diode is apparently an oven o.k. signal
>>>> that drops from 5VDC (cold) to around .8 when the oven reaches
>>>> operating temperature in around 3 minutes. This probably could
>>>> go to the base of a transistor with or gate input if you want to
>>>> use it to drive an LED. 0-5DVC on the EFC pin changes the output
>>>> by about 28Hz
>>>>
>>>>  -Arthur 
>>
>
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