NE555 time base integrated circuit diagram

One-piece inductor

The 555 integrated time base circuit, also known as the integrated timer, is a hybrid small-scale integrated circuit that contains analog circuit functions and digital circuit functions. Time-based integrated circuits have the characteristics of low cost and flexible use. As long as a small number of components such as resistors and capacitors are externally connected, many practical circuits can be constructed, such as a delay circuit that generates precise timing and a multi-resonant circuit, and thus Computers, electronic control, electronic detection, alarm, timing, signal generation, etc. have a wide range of applications.

The 555 time-base integrated circuit is a digital integrated circuit. It is a timer consisting 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 comparator's reference voltage is provided by a voltage divider consisting of three 5K resistors. They make the non-inverting input of the high-level comparator A1 and the inverter and input of the low-level comparator A2 have reference levels of 2/3VCC and 1/3VCC, respectively.