تحميل كتاب ملخص الوحدة 1،2 2019 2020 للصف الثاني عشر في مادة التصميم موقع المناهج الإماراتية الفصل 1 من العام الدراسي 2019 2020 مجموعه مؤلفين PDF

تحميل كتاب ملخص الوحدة 1،2 2019 2020 للصف الثاني عشر في مادة التصميم موقع المناهج الإماراتية الفصل 1 من العام الدراسي 2019 2020 pdf 2020م - 1443هـ The 555 timer is a single-chip version of a commonly used circuit called a multi-vibrator. • It is used in a variety of timers, pulse generators, and oscillator applications. • The 555 timer IC contains a lot of transistors, resistors and diodes. It has three 5 kΩ resistors, thus has the name 555 timer. • We use 555 timers to produce an oscillated output. • For example, we can use a 555 timer to make an LED blink ON and OFF. • 555 timers allow us to choose how frequently this blinking should occur (frequency). If we control the frequency, we are indirectly controlling the time, thus the name ‘timer’. • The chip can be used for timing functions such as - turning on a light for a period of time, a warning light to flash on/off and produce musical notes. • The 555 timer IC operates in three modes which are, astable mode, monostable mode, and bistable mode. .