Change Number of Posts Displayed on Taxonomy Template Page

Here is how to change the number of posts that are display on a Taxonomy Template page within WordPress. So let’s say you want to show 20 posts of two different taxonomies but want the blog to show the default number of posts. Add the following to your functions.php template:

// Change the number of posts that show up on the taxonomy template for Products
 function custom_tax_post_count ( $query ) {
        if (($query->is_tax(array('product_categories', 'faq_taxonomy')) ))      
        $query->set( 'posts_per_page', '20' );
    }
     add_action( 'pre_get_posts', 'custom_tax_post_count' );