Flashing LED

Alternate red and green flashing LED using 9 volt battery Part list R1,R2 – 100 Ohm R3,R4 – 105 K C1,C2 – 10 μF 25 Volt T1-T2 – BC 548 D1-D5 – Red LED D6-D10 – Green LED 9 Volt Battery

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Dark Sensor

Dark Sensor

Dark sensor using 2 transistor BC547 When light falls on LDR, its low resistance drives the transistor T1 into conduction. This keeps transistor T2 cut-off due to low base bias. The LED does not get power as long  as ambient light…

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