### Author Topic: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers  (Read 866 times)

0 Members and 1 Guest are viewing this topic.

#### EEVblog

• Posts: 33164
• Country:
##### EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« on: June 14, 2021, 01:06:26 am »
Fundamentals video. Voltage dividers, series and parallel resistors, current dividers, a revisit of Norton and Thevenin's theorems, rules of thumbs, and a trap for young players experiment on circuit loading.

00:00 - Intoduction to voltage dividers
01:33 - Uses of voltage dividers
04:27 - Rules of thumb
06:55 - Calculations
08:57 - Current dividers
10:56 - Let's revisit Thevenin & Nortons Theorems
17:29 - Experimental trap for young players

The following users thanked this post: JustSquareEnough

#### Brumby

• Supporter
• Posts: 11058
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #1 on: June 14, 2021, 02:38:13 am »
I prefer to remember the parallel resistor formula this way:
$$\frac{1}{Rt} = \frac{1}{R1} + \frac{1}{R2} + \frac{1}{R3} + \frac{1}{R4} + ...$$
It is algebraically identical to the way Dave presented it, but I find it clearer - and it follows a similar pattern as the series resistor formula:
$${Rt} = {R1} + {R2} + {R3} + {R4} + ...$$
« Last Edit: June 14, 2021, 02:42:23 am by Brumby »

The following users thanked this post: JustSquareEnough

#### JustSquareEnough

• Supporter
• Posts: 85
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #2 on: June 17, 2021, 10:37:15 pm »
another great fundamentals video, Dave. thank you.

#### EEVblog

• Posts: 33164
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #3 on: June 18, 2021, 12:57:09 pm »
I prefer to remember the parallel resistor formula this way:
$$\frac{1}{Rt} = \frac{1}{R1} + \frac{1}{R2} + \frac{1}{R3} + \frac{1}{R4} + ...$$
It is algebraically identical to the way Dave presented it, but I find it clearer - and it follows a similar pattern as the series resistor formula:
$${Rt} = {R1} + {R2} + {R3} + {R4} + ...$$

That's how I think of it too, but ultimately you have to move that 1/ to the other side of the equation to get the final result.
Waiting for the siemens fanboys...

#### Alti

• Regular Contributor
• Posts: 218
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #4 on: June 18, 2021, 02:23:30 pm »
I prefer to remember the parallel resistor formula this way

I prefer this one. Works for any i,j from 1 to N and this is one division only:

$$Rt = \frac{\prod_{i}^{}Ri}{\sum_{j}^{} \prod_{i\neq j}^{}Ri}$$

• Newbie
• Posts: 3
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #5 on: June 25, 2021, 12:34:28 am »
You're using your calculator, anyway ... and it has a "1/x" button, so the clean version is easy enough to implement.

Tom

#### Vincenzo

• Regular Contributor
• Posts: 63
• Country:
##### Re: EEVblog 1399 - Electronics Fundamentals: Voltage Dividers
« Reply #6 on: July 07, 2021, 01:02:40 pm »
Dave,
I bet we all grew up collecting fun notes just like the guy who started Wolfram, the most fun websites for nerds. I want to share a few pages of my notes that are relevant and hope that you and readers find them fun just like I did one day.

Smf