Stroboscope is a device used to make a cyclically moving object appear slow-moving or stationary. This is realised by illuminating the object intermittently with short pulses of light. Stroboscope is used in the study of insect flight. It can also be used for experiments with simple pendulum, studying details of rapidly moving objects and strobo-animation. Here is the circuit of a stroboscope that produces dual-coloured light pulses (refer Fig.1). The circuit uses red and green LEDs as light sources to illuminate the object. You can choose the frequency of the stroboscope’s light pulses from a wide range of 5 Hz to 5 kHz as desired. The range of frequency (5-50 Hz, 50-500 Hz, 500 Hz-5 kHz, etc) is selected through capacitors Ca (C2, C3 and C4), Cb (C5, C6 and C7) and Cc (C8, C9 and C10). Circuit diagram : Dual-Colour Stroboscope Circuit Diagram Smooth variation of the frequency range is achieved by varying VR1. The length of the light pulses (both red and green pulses are of equa...