Skip to main content

555 frequency genrator (astable mode)

By
The 555ic  has a ability to be used in astable  and monostable circuits.the astable mode of 555 is also called as free running oscillator because no external trigger is required to generate  a output frequency(HIGH. LOW)
The output frequency can be  changed by changing the the value of resistors R1&R2 and value of capacitor c1
In astable mode the output frequency alternates between vcc &0v on a continous bias
Working
In the above  circuit trigger & threshold pins are connected each other which allows the circuit re-trigger itself on each cycle and opreates a free running oscillator. the capacitor gets charged through both resistors but discharges only through resistance R2 the discharge  pin of timmer ic is connected to other side of resistance R2
The capacitor charges  upto 2/3 vcc (upper comparator limt)which is determined by the 0.693(R1+R2)C the capacitor discharges itself down to 1/3vcc(lower comparator limt)and is determined by0.693(R2.C) this generates a rectangular waveform output
The output frequency are determined by the resistors and capacitor

Frequency of astable mode of 555ic  is determined by this formula





Comments

Post a Comment

Popular posts from this blog

Resistance

By
The opposition offered by a substance to the flow of electric current through them is called resistance All materials oppose the flow of electric current through them i,e they have resistance Since the current is the flow of free electrons, resistance is the opposition offered by the substance to the flow of free electrons.this opposition occures because atoms and molecules of the substance obstruct the flow of these electrons .certain substances  offer very little opposition to the flow of electric current are called conductors e,g copper ,aluminium ,silver etc On the otherhand substances which offers high opposition to the flow of electric current  are called insulators e,g glass, rubver mica etc The resistance is the friction offered by the substance and causes production of heat with the flow of current.the moving electrons collide with the atoms or molecules of the substance, each collision resulting in the liberationof minute quantity of heat The unit of resistance...
Post a Comment
Read more

Comparator

By
When ever we need to  compare two analoge voltages and to find which one is greater or small the device comparator is used A comparator is electronic device that compares two analog voltages and gives output . It gives output in digital form i,e 0s and 1s and is same about the voltage present on vcc pin of comparator It has five pins two pins powering the device and other two pins are comparing pin which compares  analog voltage i,e inverting pin and non inverting pin and finally one output pin which gives digital output A comparator is made of high gain differential amplifier Comparator is used in devices such as amplifier , to convert analog signal into digital ,as measuring device etc The terminal with + sign indicates non inverting input and -signed terminal indicates inverting input Working: The output is high(1) if voltage on + terminal is heigher than on- terminal I,e v out  ={ 1,if +>-} If voltage on non inverting terminal is lower than on invertin...
Post a Comment
Read more