EEVblog 1399 - Electronics Fundamentals: Voltage Dividers

[EEVblog]

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

[Brumby]

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:
$${Rt} = {R1} + {R2} + {R3} + {R4}  +  ... $$

[JustSquareEnough]

another great fundamentals video, Dave. thank you.

[EEVblog]

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]

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:

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

[legrady]

You're using your calculator, anyway ... and it has a "1/x" button, so the clean version is easy enough to implement.

Tom

[Vincenzo]

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.