Understanding IC 555. Design note 3

We all used IC 555 in many applications. Why it is called as 555 Timer? There are three 5K resistors inside the IC that makes it as versatile IC for Timer applications. IC555 was introduced in 1971by the Signetics corporation as SE555 / NE555 and was called as IC555“IC Time Machine”. Later its CMOS version IC 7555 and Dual Timer IC 556 were introduced.
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Unusual 555 Oscillator. Unusual Design. 3

IC555 is making me happy. This tiny chip can be exploited in many ways. Here I am using Output pin3 and Threshold pin 6 to make an Audio oscillator. Another unusual way to design an Astable.
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555 Sound Transmitter. Unusual Design 2

Not satisfied with IC 555 design. Now I am going to exploit its Control voltage pin 5. This pin is used to give a controlled voltage to control the working of the Flip-Flop inside the IC. But if it is not used, it will be connected to the ground through a 0.01 disc capacitor. I am going to give a minute voltage into this pin. Let us see what happens.

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CD 4011 Astable

CD 4011 contains four 2-input NAND gates in a single package. All the gates are independent in operation except for the common power supply and ground. CD 4011 comes in the 14 pin DIP (Dual In Line Package). Unlike other digital integrated circuits, all the unused inputs of the IC should be either connected to the positive rail or ground. No inputs should be left floating as this may cause erratic operation of the IC.

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IC 555 Astable Mode

Timer IC 555 is widely used in both analogue and digital circuits to generate short duration pulses. It can be designed as Monostable and Astable multivibrator and also as Bistable, Schmitt trigger etc. In the Astable Mode, the output gives high and low pulses based on the value of timing resistor and timing capacitor. The Note given here is useful to calculate the frequency of oscillation and timing cycle.

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