Would someone proof this schen

[blueherdim7]

Hello all-

I wonder if someone more knowledgeable than me would look at this schem for me.  I want to put a switch in this kay fuzz schem to switch between germanium or silicon diodes.  This is my first attempt with eagle, so just want some help to make sure I have drawn it correctly.

https://www.yousendit.com/download/U0d6MWZERnczS3BMWEE9PQ

Thanks

Jon

[Cliff Schecht]

Two things:
1. That won't work. No matter what position the switch is in you're going to be connecting both diode pairs at the same time. You need a single-pole, double-throw (SPDT) switch, you only have an SPST variant.
2. You don't need to place a junction on every junction where a part connects in Eagle. The only time you need to place a junction, if one isn't placed automagically, is when three or more wires or parts connect at a single point. If you aren't sure if a part is connected, click the "move" command and move the part around. The wires should move with the part, otherwise it's disconnected. If it is disconnected, just click the part with "move" and drop it in the same place (unless you missed the pin, at which point you need to redraw the wire).

[blueherdim7]

Thanks Cliff-

That's what I was concerned with.  I will change the switch.  I know about the junctions, but with my lack of experience, placing the junctions helps me feel warm and fuzzy!  LOL.

Jon

[blueherdim7]

Looking back...I think I do have  a spdt switch in, but when I set up the pcb, all 4 diodes are in fact connected at all times.  Any suggestions?  Do I have the schem drawn correctly?

Jon

[Cliff Schecht]

Sorry, don't know why I was mixing up my switch topologies.. You have a SPDT and need a DPDT. I fixed your schematic and uploaded it here:
http://www.aronnelson.com/DIYFiles/up/Kay_Fuzz_Schem.sch.mp3

Download it and delete the .mp3 part of the extension. I cleaned up your junctions as well, they were bugging me

[Dan N]

How about> SPDT switch- pole to ground, Si diodes on left lugs, Ge diodes on right. A SP ON-OFF-ON switch gives a "none" position that can be fun.

http://users.rio.com/senorris/junk/diodeswitch.gif

Edit- Sorry Cliff, you may have had that. I just DLed Eagle and for some reason both schematics look identical, junctions and all.

[oskar]

http://www.aronnelson.com/DIYFiles/up/Kay_Fuzz_Schem.sch.mp3
Download it and delete the .mp3 part of the extension. I cleaned up your junctions as well, they were bugging me

You uploaded the original file.   

Or you can hardwire the diode pair with the highest forward voltage and use a spst switch to cut in or out the other pair (Ge)...

How about> SPDT switch- pole to ground, Si diodes on left lugs, Ge diodes on right. A SP ON-OFF-ON switch gives a "none" position that can be fun.

Or use the middle position(off) position for a third pair... your mighty LED's that are allways on but only will conduct when the others are off.

[blueherdim7]

Cliff-

Again, thanks for your help.  I can't seem to download the edited one you did.  I just get my original.  Can you help me one more time?

Cheers.

Jon

[Cliff Schecht]

Sorry yeah, I'll upload the correct file when I get home.. I'm on a cold streak 

[Cliff Schecht]

Ok, let's try this again. A SPDT switch will do the job, you just had it miswired. The link above is fixed, so use it to download the fixed schematic.

It's been a long week

[blueherdim7]

Cliff-

It still looks like the original.  Do I need to add another cap to prevent the connection of the two sets of diodes after the switch?

Jon

[Cliff Schecht]

Cliff-

It still looks like the original.  Do I need to add another cap to prevent the connection of the two sets of diodes after the switch?

Jon

Are you sure you aren't opening your original file? I'm going to upload mine one more time, under a different name. I checked it this time, the link should be the updated version..

[Cliff Schecht]

http://www.aronnelson.com/DIYFiles/up/kaytremfixed.sch.mp3

[blueherdim7]

Cliff-

I finally got home to download the schem.  Thanks so much again for your efforts!!  It looks great...

Jon