Skip to Content Go to sign in Skip to Primary Navigation Skip to Secondary Navigation Skip to Page Navigation Skip to Header Navigation Skip to Footer Navigation Read more about accessability options and our navigation

Physics Classroom is making strides to make our site accessible to everyone. Our site contains 6 navigation areas. The Primary, Secondary, and Page Level navigations have a screen reader version of their nav structure that allows using the left and right keys to navigate sibling navigation items, and up or down keys to navigate parent or child navigation items. The others can be navigated using tabs. The Primary Navigation handles the first 2 levels of site pages. The Secondary (which is not always available) handles the 3rd and 4th level of structure. The Page level navigation allows you to navigate the current page's headings quickly. The Header Navigation contains the Light/Dark Mode toggle, Search, Notifications and account login. The Breadcrumb Navigation contains the breadcrumb of the current page. If the current page has a breadcrumb, you can get to it by skipping to the content and tabbing in reverse (shift plus tab). The Footer Navigation contains links such as Privacy, Contact, about and terms. Some resources contain an Audio Player that can be activated by holding down the T key for 3 seconds, and then using K to pause and resume. While not every area of Physics Classroom is usable purely from keyboard and screen reader, we are committed to continue work on making this possible. If you have questions or need additional help, please use this link to contact us.

Return to screen reader navigation

Mission EC8 Parallel Circuits Concepts

 The Question

As more and more resistors are added in parallel to a circuit, the equivalent resistance of the circuit ____ and the total current of the circuit ____.

 Define Help

Definition of Equivalent Resistance:
The equivalent resistance of a circuit is the amount of resistance that a single resistor would need in order to equal the overall effect of the collection of resistors that are present in the circuit.

 Physics Rules

Equivalent Resistance in Parallel Circuits:
Parallel circuits are characterized by multiple pathways or branches through which charge flows. When additional resistors are placed within separate branches of a parallel circuit, additional pathways for charge flow are provided. Thus, the addition of more resistors (which also means additional pathways) has the effect of decreasing the overall resistance and increasing the overall current.

 Formula Fix

For parallel circuits, the mathematical formula for computing the equivalent resistance (Req) from the resistance values of the individual resistors (R1, R2, R3, ...) is
 
1 / Req= 1 / R1 + 1 / R2 + 1 / R3+ ... .

Return to Screen Reader Navigation