In the use of circuits, almost any electronic circuit is inseparable from the use of patch resistance. The role of the patch resistance is to increase the resistance of the current through, thus limiting the current size of the branch connected through it. However, due to the different application circuit, the requirements for its resistance value are not the same, therefore, learn to see the size of the resistance of the patch is a very important aspect. So how to look at the size of the patch resistance?