Timer, LM555 datasheet, LM555 circuit, LM555 data sheet : NSC, alldatasheet, datasheet, Datasheet search site for Electronic Components and Semiconductors, integrated ... Timer, LM555 datasheet, LM555 circuit, LM555 data sheet : NSC, alldatasheet, datasheet, Datasheet search site for Electronic Components and Semiconductors, integrated ... circuits into the ever increasing ranks of timer users. DESCRIPTION The 555 timer consists of two voltage comparators, a bistable flip-flop, a discharge transistor, and a resistor divider network. To understand the basic concept of the timer let’ s first examine the timer in block form as in Figure 1. The effect is quite dramatic. For a great resource on the 555 timer, OpAmps, and other IC’s check out the Engineer’s Mini Notebook: Timer, Op Amp, and Optoelectronic Circuits & Projects. There are 24 different 555 timer circuits in this book! Click here to continue on to part 2 of this series, 555 Timer Basics – Bistable Mode. Aug 29, 2015 · The IC555, popularly known as the 555 Timer, was developed by Hans Camenzind of Signetic Corporation in the year 1971.. It was released in two parts: NE 555 and SE 555. The NE 555 parts were of commercial usage with a temperature range of 0 0 C to 70 0 C and the SE 555 parts are designed to meet the military standards with a temperature range of -55 0 C to 125 0 C. circuit. PULSE WIDTH MODULATOR When the timer is connected in the monostable mode and triggered with a continuous pulse train, the output pulse width can be modulated by a signal applied to pin 5. Figure 8 shows the circuit, and in Figure 9 are some waveform examples. DS007851-9 VCC = 5V Top Trace: Output 5V/Div. TIME = 20µs/DIV.