Take the 2-minute tour ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.

In this schematic, there is an unfamiliar notation for the variable capacitors using and division sign or obelus, for example 2÷10p (red), as opposed to, e.g. 1p for a fixed capacitor (green).

Schematic fragment

I have presumed that this is used for indicating the number of air gaps in a rotary variable capacitor, as the total capacitance is the capacitance of one gap, divided by the number of gaps (or plates - 1):

\$\frac{C_{one\ gap}}{n_{gaps}} = \frac{C_{one\ gap}}{n_{plates} - 1} = C_{total}\$

Is this the correct interpretation?

share|improve this question
add comment

1 Answer 1

up vote 4 down vote accepted

By Occam's razor, I would interpret the markings as the range of capacitance for the trimmers, and that it's a regional or idiosyncratic use of ÷ rather than ~ or -.

This is confirmed by the text on the website- for example here.

Capacitive trimmers (Philips foil type, 7.5mm diameter with three leads) in the 106MHz and 213MHz bandpass filters are increased to 5-40pF (violet body), while the trimmers in the output stage at 425MHz are increased to 4-20pF (green body).

Mechanical engineers sometimes indicate ranges by putting one number above the other, separated by a horizontal line, which, of course, is what ÷ is shorthand for.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.