IC 555 Basics
IC 555 is one of the most commonly used timer circuit IC, hart of many hobby circuit and it have a widespread application in electronic gadgets and circuits. Here we note some useful application notes and circuits to help electronics hobbyist, circuit developers and students.
The 555 is named, so because two comparator of this ic is connected with 5K resistance as a voltage divider to bias the comparator.
Pin configuration of IC 555
Pin No. 1 : Ground
Pin No. 2 : Trigger (output go high when voltage reach 1/3 Volt )
Pin No. 3 : Output
Pin No. 4 : Reset
Pin No. 5 : Control voltage (this latch output go low)
Pin No. 6 : Threshold ( Output go lo when voltage reach 2/3 Volt)
Pin No. 7 : Discharge ( It will connected to ground when output low)
Pin No. 8 : Supply voltage (range + 4.5 Volt to + 16 Volt
IC 555 Timer with LDR
IC 555 Timer connected with a LDR, The Resistance variation of LDR depends on intensity of light makes the variation of frequency.