If you’ve ever been designing a circuit and had to experiment with different values of caps and resistors, you probably didn’t like it much. It can be a hassle to switch out components over and over, trying to find the right combination to suit your needs. With RC filter circuits, it can be quite difficult to determine what resistance and capacitance you need to get the filtering attributes you want. With a Selection box such as this just a turn of a knob can test many different values.
Build a Resistor/Capacitor Selection Box – [Link]