XPost: sci.electronics.design
From: erichpwagner@hotmail.com
On 09/11/2020 2:06 pm, Don wrote:
> In sci.electronics.design piglet wrote:
>> On 08/11/2020 9:08 pm, Don wrote:
>>> This project shows how to build a 1.5 VDC pseudocell to take the place
>>> of an AA sized battery. The mechanical aspect of this project offers the
>>> greatest challenge. The electronic portion utilizes an easy to use LM317
>>> adjustable voltage regulator to convert a 5 VDC source to 1.5 VDC.
>>>
>>> (excerpt)
>>>
>>> https://crcomp.net/pseudocell/index.php
>>>
>>> (Thank you In Advance to readers who alert me to typos and whatnot.)
>>>
>>> Danke,
>>>
>>
>> Your circuit design description states that R3 provides the minimum 10mA
>> load current. Yet the value of R3 is 15k which only draws 0.1mA which
>> when added to the R1/R2 divider current of 1.13mA means the minimum load
>> on the LM317 is only 1.2mA far short of the stated 10mA
>>
>> You don't even need R3 - just change R1 to 120R and R2 to 24R.
>
> Excellent! (As always, BTW.)
> Looks like my worst fear was realized as sloppy discipline allowed
> a decimal point to slip down from mils to micros. Your hint about how
> to eliminate R3 is much appreciated too.
> My approach to technology previously untapped by me is to approach
> it with caution. And a R2 of hundreds of ohms somehow seemed safe, until
> you helped me see things clearly in my mind's eye.
> Anyhow, the perfboard will be quickly rebuilt with correct
> components. It's mounted on an easily accessed backboard and plugged
> into a strip connected to the UPS used for the phone system. The last
> bit doesn't matter much, given how a long pole will be used to correct
> the clock's drift.
>
> Danke,
>
Thanks Don, you are very welcome.
piglet
Science teaches us to verify.
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