NE555 time base integrated circuit diagram

The 555 integrated time base circuit is also called an integrated timer. It is a hybrid small-scale integrated circuit that contains analog circuit functions and digital circuit functions. Time base integrated circuits have the characteristics of low cost and flexible use. As long as a small number of external resistors, capacitors and other components are connected, many practical circuits can be formed, such as delay circuits and multi-vibrator circuits that produce precise timing. Therefore, in micro It has a wide range of applications in computers, electronic control, electronic detection, alarms, timing, signal generation, etc.

The 555 time base integrated circuit is a digital integrated circuit. It is a timer composed of 21 transistors, 4 crystal diodes and 16 resistors. It has functions such as voltage divider, comparator, flip-flop and discharger. It contains two voltage comparators, a basic RS flip-flop, and a discharge switch T. The reference voltage of the comparators is provided by a voltage divider composed of three 5K resistors. They respectively make the non-inverting input of high-level comparator A1 and the inverter of low-level comparator A2, and the reference level of the input end is 2/3VCC and 1/3VCC. As shown in the figure below.