A monochromatic light source (single color or single frequency) may be useful in the physics laboratory for conducting optics experiments. The source we describe uses LEDs, which are monochrome light sources that can be found in a variety of colors. It will be interesting to have fonts in basic colors, red, green and yellow, as well as other less common such as blue.
The circuit is simple and can be powered by batteries. In figure 1 we have the complete circuit for two LEDs and in figure 2 its assembly in a small terminal strip.
An interesting possibility is that using the RGB (Red-Green-Blue) LED that produce the three basic, can be combined to generate white or any other color.
Material list
LED1, LED2 - LEDs of any color (except white)
R1- 47 ohm x 1/8 W - resistor - yellow, violet, black
B1- 6V - 4 small batteries
S1 - Pushbutton or single switch
Miscellaneous: terminal strip, battery holder, wires, mounting box, etc.
