Is there a way to draw this schematic a little more refined?


Another thought?

Maybe don’t turn the graphic line into a complete box… IMHO this also helps reduce the noise and clutter.

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As the subcircuits are all identical, this would be a good case for a hierarchical design. You can design your switch interface on one sheet and instantiate multiple copies of it in your master sheet. It will make this easier to maintain.


If you create a new symbol for your switch with two parts (like the individual gates in a 74 series logic part), you can create a clearer schematic with no crossings. This also shows the center off position of the switches that gives the 5n capacitance.


Because I can only do one like. :+1:

@ Dennisch
That’s very ambiguous to say the least.
Drawing a switch like that is open to misunderstanding, Indeed, it’s misleading.
Having the capacitor wires crossing and keeping the switch action coherent is much better.


Yes, I thought about that option as well. But hierachical sheets do not lend themselves well to this application. You’ll need to create each sheet individually (copying/duplicating isn’t possible).
On maintenance: You’ll need to maintain every sub-sheet individually. Not nice.

Scrap my comment above!! I just tested it. Creating multiple sub-sheets that link to the same sub-sheet file is possible. Probably the best idea after all. :slight_smile:

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Guess I need to start reading up on hierarchical sheets! :smile:

It’s good design practice to split up a complicated design. That’s not the case here.
But in this special situation it makes a lot of sense.
I’ve made an example design for you.
Open Scratchpad.sch first, that will enable the second file.
Scratchpad.sch (372 Bytes)
SW.sch (2.5 KB)

The best approach would be to create a new DPTT switch in your custom library and use that for the design (in the sub-sheet).

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You are lucky to have Kicad. In the pencil-and-paper days you had to buy the big erasers and use them a lot to make a schematic look pretty.

If the schematic in Kicad is a little messy you can use a feature I just discovered (as a super-newbie). If you hold the control button down when you click on a trace that whole net gets highlighted.

I was drawing a simple adapter between two headers. No matter how neat it’s difficult to eyeball trace one wire out of a couple dozen. If I light up the net I know immediately whether or not it’s going to the right place and if there are any accidental cross connections.

I first started using Kicad for its schematic drawing capability. Then I got a quote for duplicating an old PCB whose Gerbers were not welcome anywhere anymore. I just heard that v6.0 was out. So I down loaded it and entered my schematic.

One advantage I had was that I had a wired version of the old board and the old schematic. That helped me straighten out the rat nest and place the parts because I made the layout look like the original.

So insted of paying $$$$ for new gerbers to make maybe 3 copies of the old board I paid $ plus 30 hours of my time, which was less than the professionals estimated, plus it was a learning experience. That’s definitely win-win for me.

The trick is to find the right symbol for your part and mate it to the right footprint. So far I have found lots of free symbols for odd parts that are not in the library. They didn’t always have the same name as my part, but if the had the right pin out I could use it. Also, I realized that a lot of footprints are generic so all you need to know is the basic description.

I’m not ready to conquer the world, but I am happy to have a new arrow in my quiver.


My guess is that it is a 2-pole switch because the caps can directly be soldered onto it. If there is a PCB for the caps then it would possibly be single pole (or both poles in parallel to last longer). Duplicate symbol SW_DPDT_x2 and modify unit A (and B):

I don’t understand your post at all. The OP’s post was completely clear on this, it’s a DPDT with middle position (aka DPTT, aka On-Off-On).
Why are you throwing confusion into this?

Yes, its a DPDT On-Off-On :+1:

You could connect pin 4 with 5 and 6, and it would still work the same…

Unless you are making a well…?

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That would short-circuit one side of the switch. I’m convinced that that’s not the asker wants

Friendly advice: “When you’re in a hole, stop digging…”

Unfortunately not, I’m using the DPDT On-Off-On to toggle between 3 capacitance values in parallel.

On position is 5nF shorted across pins 2 & 5 + 5nF from pins 1 & 4 giving a value of 10nF
Off position is 5nF shorted across pins 2 & 5 giving a value of 5nF
On position is 5nF shorted across pins 2 & 5 + 10nF from pins 3 & 6 giving a value of 15nF

I would probably call it 2-pole change-over or DPCO/DPDT/2P2T with (break/neutral) center position. Or DPTT/2P3T with unassembled mid-contacts. A pole corresponds to a unit in KiCad.

With 2P, the two capacitors are basically connected with 2 contacts in series, which increases the open resistance but also the closed resistance and possible eventual noise if the contacts get dirty, compared to 1P. Two contacts in parallel could improve it. Depends on the switch quality and other factors.

Here the leftmost drawing style would be what I prefer for clarity / ease to read and intuitively understand (quickly).

This seems to be audio frequency stuff.
Is there a reason why one would want to switch both sides of the capacitors instead of just one, and connect the other side permanently?
That is, is there a problem with having one side permanently connected and the other switched, and when not connected, the one side of the capacitor is just “hanging in the air” and following the signal?

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