Can you please help advice on switch

Thread Starter

leonahom

Joined Aug 4, 2017
3
Hi All,

I am trying to find a switch for the attached circuit. I am not an electronics engineer and generally struggle with components that must be all to familiar to you. The thing I want to achieve is that when the switch is in position 'A' it should connect terminals 1, 2 & 3 to the terminals of the IC at the same time. And when the switch is in position B it should connect terminals 4, 5 & 6 to the IC. If it is a surface mount type slide or toggle switch that will be ideal. Any help will be much appreciated. Many thanks

20170804_154953_resized.jpg
 

AlbertHall

Joined Jun 4, 2014
12,344
You need a three pole, double throw switch, known as 3PDT.
Plenty available in different styles but I couldn't find and surface mounted.
 
I see you don't have current limiting resistors on the LED lines. Does your "IC" drive enough current and voltage to turn LEDs on?
Small SMD general propose BJT transistors should work here.
 

Thread Starter

leonahom

Joined Aug 4, 2017
3
I see you don't have current limiting resistors on the LED lines. Does your "IC" drive enough current and voltage to turn LEDs on?
Small SMD general propose BJT transistors should work here.
Thanks Varam, yes the IC delivers constant current and required voltage to the LEDs. I am afraid the switching needs to be mechanical for this project.
 

Reloadron

Joined Jan 15, 2015
7,501
Something I don't understand. When the switch is in for example Position A your terminals 1, 2 and 3 are connected to your IC. OK, we assume the IC takes care of voltage and current limiting to the LEDs. Position 1 will be a +V and position 2 Common and illuminate the top row of LEDs. However for the bottom row to illuminate wouldn't we need a negative voltage? A voltage less than the common applied at position 2? Unless the IC is doing a toggle of sorts. Position #2 ties to the cathodes of the upper row and the anodes of the lower row (third row down). I guess I just don't see what the effect would be? That is my question, if we make the contacts as desired what will the LEDs be doing?

Ron
 
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