10 Mar
2013
10 Mar
'13
12:22 p.m.
Well, I assumed it was doing a simple V R ratio / sum-of-logs of two
of the controls with a null-point balance with the third, however one
of the sites on the web showed a bag of caps and transistors involved
in the construction so perhaps it's using some AC principle, or that
may be a mislead.
I'm going to try to find the PE article in the library at the radio
museum this afternoon.
On 2013 Mar 10, at 11:50 AM, dwight elvey wrote:
I did some searching on the web but I was
surprisedthat no one has
posted a schematic for it.Dwight
> Actually, after giving it a little thought, it would use
> linearpots and scales. It would be voltage dividers and a
> balancingmeter.Remeber, a pot forms a ratio across a resistor.Dwight
>> From: hilpert at cs.ubc.ca
>
>>
>> That's what I was expecting, but looking at the dial (as much as one
>> can see in the photos), they appear to be linear, so I figured it
>> was
>> taking advantage of log pots (or is there a log/anti-log problem
>> there anyways?). Considering it more, a typical log pot may not give
>> an accurate enough log function to be very good for the task, so
>> you're probably right. Maybe there's another principle involved.
>>
>> Another web site refers to a popular electronics article with a
>> similar design (I think I've seen the article in the past) but
>> doesn't say which issue.
>>
>>
>> On 2013 Mar 8, at 8:58 PM, dwight elvey wrote:
>>> Actually it makes more sense to use alinear one with log scales on
>>> the dial.Dwight
>>>> From: hilpert at cs.ubc.ca
>>>> ---snip---
>>>>
>>>> I like how the box says "As accurate as a slide-rule".
>>>>
>>>> Presumably it uses standard log pots, aka volume controls.
>>