# Are the 3 resistors in parallel or in series?

Are $$\R_1\$$, $$\R_3\$$, and $$\R_2\$$ in series? or are $$\R_1\$$ and $$\R_2\$$ in parallel? I'm new to all this. Here's the circuit:

Well, $$\\text{R}_3\$$, $$\\text{R}_4\$$, $$\\text{R}_5\$$ and $$\\text{R}_6\$$ are in parallel and they are in series with $$\\text{R}_1\$$ and $$\\text{R}_2\$$.

simulate this circuit – Schematic created using CircuitLab

So the total resistance is:

$$\text{R}_\text{total}=\text{R}_1+\text{R}_2+\frac{1}{\frac{1}{\text{R}_3}+\frac{1}{\text{R}_4}+\frac{1}{\text{R}_5}+\frac{1}{\text{R}_6}}$$

• so i get the equivalent resistance of R3 R4 R5 and R6, then i add it to r1 and r2, so r1 and r2 are in series ? Commented Mar 26, 2020 at 14:50
• @AhmadBenos See my edit Commented Mar 26, 2020 at 14:51
• Got it! Thanks a lot. Commented Mar 26, 2020 at 14:51
• @AhmadBenos You're welcome, I'm glad that I could be of any help. Commented Mar 26, 2020 at 14:54

• Two resistors are in parallel if each terminal of resistor A is connected to the terminals of resistor B
• Two resistors are in series if only one terminal of resistor A is connected to a terminal of resistor B (and their common point isn't connected to anything else).

Just because it's worth saying: it doesn't matter how you draw them, it only matters how you connect them.

As for solving these kinds of problems, you can always replace two parallel resistors with another resistor of value 1/( 1/Ra + 1/Rb ), regardless of what other connection there might be. (Series resistors, on the other hand, can only be replaced by a single resistor if nothing else is connected to their common point.)

simulate this circuit – Schematic created using CircuitLab

• I want to deny the fact that the 3rd figure of parallel figures is not series but parallel.. Commented Jun 6, 2020 at 14:05
• The definition of series is not correct. Elements are in series if just one terminal of each element is connected to together and nothing else is connected at that point. I know that you say that this is a condition for resistors to be combined, but it is actually a condition for them to be in series. Commented Jun 6, 2020 at 17:21
• @ElliotAlderson thanks for your comment. How would you describe the two resistors of a potential divider across say power and ground? We add their resistances to calculate the load they present to the power supply, because they are in series. Even when we connect (say) the base of some transistor there, those resistors are still in parallel. How would you describe them? Commented Jun 7, 2020 at 11:24
• @muyustan thanks for your comment, but I'm not sure what you're saying. Are you saying R3a and R3b are not in parallel? Commented Jun 7, 2020 at 11:25
• As long as you have just the two resistors forming the divider then they are in series. The important aspect is that the current through them must be exactly the same...the voltage divider equation depends on that. When you connect something else at the point where the two resistors connect then the two resistors are no longer in series...the current through them may be different. It is absolutely vital that we keep this in mind. You could say that "as long as the base current is much much smaller than the divider current, then the two resistors still work like a voltage divider". Commented Jun 7, 2020 at 13:24

Resistors R3, R4, R5 and R6 are connected in parallel. And this circuit is connected in series to R1 and R2.

• Oh okay! Thanks Commented Mar 26, 2020 at 14:51

Actually R3,R4,R5,R6 are in parallel combination as the voltage across the resistors is same and the combination and R1,R2 are in series as the current will be same through them

• Isn't this exactly what all of the answers said? Commented Mar 28, 2020 at 15:17