Switch in schematic has me confused - Page 1
Forum section: electronics / projects

author: JaiKai
author_rank: Newbie
timestamp: August 11, 2018, 12:57:33 am
content: Hey guys I've been looking around forever trying to figure out what this schematic is implying with the two switches and was wondering if anyone could help tell me what kind of switches are used and some help with the dotted lines and what they mean for future referenceHere is an image of the schematic I'm reading from.

author: ignator
author_rank: Regular Contributor
timestamp: August 11, 2018, 01:03:25 am
content: This is a 4 pole, double throw switch. The dashed line indicates the switch is ganged to a single toggle mechanism. Think of it as 4 single pole, double throws all ganged so they switch simultaneously.Note the designator shows this as SW1, with sections A, B, C, D.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: August 11, 2018, 02:42:53 am
content: This selects between the mike and line. It grounds the line when its not used.Sent from my SM-G930V using Tapatalk

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 11, 2018, 02:59:01 am
content: SW1 is a 4-pole, double-throw (4PDT) switch. The four sections are labeled SW1-A through SW1-DThe dashed line indicates that the sections all move together.The sections (poles) are located apart from each other to indicate their role in the circuit (rather than the physical configuration of the switch).As @ahbushnell mentioned, SW1 switches between LINE and MIC.SW2 is a double-pole, double-throw (DPDT) switch.The sections are drawn adjacent to each other, so the sections are not separately labeled.Again, the dashed line indicates that the sections move together.SW2 changes the "phase" (actually polarity) of the audio signal.

author: JaiKai
author_rank: Newbie
timestamp: August 11, 2018, 08:56:15 am
content: I had a sneaking suspicion that’s what it meant haha just wanted to confirm before I went out getting one as the 4PDT suckers are pricey and difficult to find push latching ones.Another question in regards to the gain pot it is supposed to be a reverse log d law is that just a standard C5K or is there more to this tale?Thanks for the quick replies btw!

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 11, 2018, 12:08:58 pm
content: The gain will be very difficult to adjust unless you use a reverse-log pot.There are very few to sources for reverse-log pots in retail small quantity.This is one of the rare sources that I know about. Perhaps others have other suggestions?https://www.taydaelectronics.com/potentiometer-variable-resistors/rotary-potentiometer/anti-log-reverse.html

author: alsetalokin4017
author_rank: Super Contributor
timestamp: August 11, 2018, 01:22:48 pm
content: FWIW, I've made about a dozen orders from Tayda. They are fast (to North America at least), accurate and friendly.

author: JaiKai
author_rank: Newbie
timestamp: August 11, 2018, 01:41:16 pm
content: Ahhh so my hunch was correct they are the C type pots I’m after I already have some of those but they won’t be cheap to buy a bulk load in the near future damn.Thanks for the quick replies again though guys!

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 11, 2018, 05:02:00 pm
content: Different areas and different vendors use different letter designations for pot taper curves.You should confirm that your "C-taper" pots are really reverse-loghttp://www.resistorguide.com/potentiometer-taper/

author: JaiKai
author_rank: Newbie
timestamp: August 11, 2018, 07:39:15 pm
content: Over here we still go by the pots as A=Log B=Lin and C=Rev Log I was just confused about the second portion as in the schematic it is referred to as a Reverse Log D-Law pot but I’m assuming that just means the standard reverse log which are C”resistance”K for me in the UK.