A stroboscope is an instrument which is used to view the object which is moving rapidly with a periodic motion as if they are at rest. The strobe light flashes at a frequency that synchronizes with the resolution of a wheel or moving object which seems to be at a still position. The circuit of strobe light utilize neon lamp because their light is dim to detect the fault, for good illumination a 9 inch tube-light is used.
Circuit Diagram of Stroboscope Lamp
Resistors (all ½ -watt, ± 5% Carbon)
R1, R3 = 10 KΩ
R2 = 4.7 KΩ
R4 = 6.8 KΩ
R5 = 270 Ω
VR1, VR2 = 100KΩ
C1 = 10 µF/25V
C2, C9 = 1 µF/25V
C3, C8 = 0.1 µF
C4 – C7, C10 = 0.01 µF
IC1, IC2 = NE555
T1 = 2N3055
X1 = 220V AC primary to 0-6V, 500mA secondary transformer used in reversed mode.
SW1 = Single pole 4-way switch
SW2 = Single pole 3-way switch
9 inch fluorescent tube.
Circuit Description of Strobe Light
The circuit of strobe light is wired easily available timer IC NE555 (IC1, and IC2). IC1 is wired as astable multivibrator whose frequency can be varied over 1:10 range through variable resistor VR1. Rotary switch SW1 is used to select the range with proper adjustment this astable mode can be generate 1.2 Hz to 12 KHz frequency.
The output of IC1 from pin 3 is given to pin 2 of IC2 through coupling capacitor C6. The IC2 is wired as monostable multivibrator whose output pulse width can be varied from 100 µs to 100 ms with the help VR2. Rotary switch SW2 is used to select the range.
The output of IC2 from pin 3 is given to base of transistor T1 through current resistor R5. The output of transistor is connected to secondary transformer. The transformer X1 (6V-0V secondary) is used in reverse mode (i.e. step up mode). The 6V terminal is connected to 12V DC supply and 0V to output of transistor as shown in circuit diagram of strobe light (figure 1).
Oscillating current are generated in 6 volts winding as per our adjustment and stepped up to light the tube light. The tube-light is focused on tatting table fan blade and the frequency and pulse width is adjusted so that both are synchronized. This happens when the fan blades seem to be stand-still.
Note: If anyone wants to use bigger tube-light, a suitable driver stage and inverter transformer is essential.