logo of the website RF Wireless World

555 timer calculator and formula

The 555 timer IC is one of the most widely used versatile ICs in the field of electronics. It is known for its simplicity, reliability and flexibility. This timer operates in various modes but it is most commonly used as monostable multivibrator and astable multivibrator. These are configurations to generate timed pulses and square waves respectively.

Astable Mode (Oscillator Mode):
In this mode, the 555 timer generates a continuous square wave output. It's commonly used for generating clock signals, tone generation in electronic music, and other applications where a continuous waveform is needed.

Monostable Mode (One-Shot Mode):
In monostable mode, the 555 timer produces a single, precise pulse output in response to an external trigger. The duration of the pulse is determined by external components and can be adjusted as needed. This mode is often used for time-delay circuits, pulse shaping, and other applications requiring a single pulse.

Let us explore 555 timer calculator including calculations in monostable and astable modes. In monostable mode, 555 timer calculates pulse width. In astable mode, it calculates frequency and period.

555 monostable calculator #1

As mentioned this 555 timer monostable calculator is used to calculate pulse width based on R and C inputs.

Resistance in KΩ (input1) :

Capacitance in µF (input2) :


Output Pulse Width in sec (output1) :

EXAMPLE #1 555 timer calculation in monostable mode:
INPUTS: R = 10 KΩ , C = 47 µFarad ,
OUTPUT: Output pulse width, Tp = 0.517 sec

555 monostable formula

Following is the 555 monostable formula used in the above calculator #1.


555 timer calculator monostable mode

Length of output pulse or pulse width (Tp) = 1.1*R*C
The R and C are shown in the figure.

555 astable calculator #2

As mentioned this 555 timer astable calculator is used to calculate frequency, period, high time and low time based on C, R1, R2 inputs.

Capacitance (C1) in µF (input1) :

Resistance (R1) in KΩ (input2) :

Resistance (R2) in KΩ (input3) :


Time High, sec (output1) :

Time Low , sec (output2) :

Pulse Frequency, Hz (output3) :

Pulse Period, sec (output4) :

Duty Cycle, % (output5) :

EXAMPLE #2: 555 timer calculation in astable mode:
c1=100µF, R1=R2=10 Kohm
tHIGH = 1.386 sec , tLOW = 0.693 sec, Pulse Frequency= 0.481 Hz , Pulse Period = 2.079 sec , Duty cycle = 66.67%

555 astable formula

Following is the 555 astable formula used in the above calculator #2.

555 timer calculator astable mode

tHIGH = 0.693*C1*(R1+R2)
tLOW = 0.693*C1*R2
Pulse Frequency = 1/(tHIGH + tLOW)
Pulse Period = 1/Pulse Frequency
Duty Cycle = (R1+R2)/(R1+2*R2)

Conclusion : In summary, 555 timer calculations and formulas in monostable and astable modes offer precision, versatility, cost-efficiency, and educational value, making the 555 timer a valuable component in the world of electronics and circuit design.

Useful converters and calculators



Posts on electronic components

Ohm Law   Inductor basics   Resistor basics   Capacitor basics   Transducer  

RF and Wireless tutorials

WLAN  802.11ac  802.11ad  wimax  Zigbee  z-wave  GSM  LTE  UMTS  Bluetooth  UWB  IoT  satellite  Antenna  RADAR 

ARTICLES   T & M section   TERMINOLOGIES   Tutorials   Jobs & Careers   VENDORS   IoT   Online calculators   source codes   APP. NOTES   T & M World Website  

Search this website

RF Wireless World

RF Wireless Tutorials



Calculators & Converters

Calculator Main Index Page
ppm to Hz converter
LTE EARFCN Vs Frequency
UMTS UARFCN Vs Frequency
GSM ARFCN Vs Frequency
Parabolic Dish Antenna
Circular Waveguide Fc
floating vs fixed point
Channel Capacity Calculator
Radar Range calculator
Cascaded IP3 Calculator
MTBF and MTTF Calculator
Power Unit Conversions

Popular Tutorials

DECT  ISDN  ATM  WBAN  TransferJet  BLE  Femtocell  HSPA  BACnet  Ethernet  TETRA  Underwater wireless  5G  LiFi  LoRa  NFC  Infrared  RF measurements  VSAT  Diode  SS7  Networking  Network Security  FTTH  KNX  WAP  Mobile IP

两个鬼故事张姓女马宝宝起名村庄起名起什么好马伯庸《洛阳》小说起名字女孩2020年鼠宝宝教育起名字花卉园艺起名瓷都姓名测试单车比赛男人瑞字起名字新超市起名氏薛宝宝起名没有攻击力的神牧店透视july几月书吧起什么名字好笙起名寓意端午节祝福语2021最火郭姓女孩取名起名大全高端大气刘姓男孩100起名起个带财的名称仙侠游戏起名寓意好的成语起什么名字好臧姓男生起名gbc游戏下载中国夏令时起名改名大师兽兵卫忍风帖写给工作室起名字大全世子很凶猪年男起名宜用字少年生前被连续抽血16次?多部门介入两大学生合买彩票中奖一人不认账让美丽中国“从细节出发”淀粉肠小王子日销售额涨超10倍高中生被打伤下体休学 邯郸通报单亲妈妈陷入热恋 14岁儿子报警何赛飞追着代拍打雅江山火三名扑火人员牺牲系谣言张家界的山上“长”满了韩国人?男孩8年未见母亲被告知被遗忘中国拥有亿元资产的家庭达13.3万户19岁小伙救下5人后溺亡 多方发声315晚会后胖东来又人满为患了张立群任西安交通大学校长“重生之我在北大当嫡校长”男子被猫抓伤后确诊“猫抓病”测试车高速逃费 小米:已补缴周杰伦一审败诉网易网友洛杉矶偶遇贾玲今日春分倪萍分享减重40斤方法七年后宇文玥被薅头发捞上岸许家印被限制高消费萧美琴窜访捷克 外交部回应联合利华开始重组专访95后高颜值猪保姆胖东来员工每周单休无小长假男子被流浪猫绊倒 投喂者赔24万小米汽车超级工厂正式揭幕黑马情侣提车了西双版纳热带植物园回应蜉蝣大爆发当地回应沈阳致3死车祸车主疑毒驾恒大被罚41.75亿到底怎么缴妈妈回应孩子在校撞护栏坠楼外国人感慨凌晨的中国很安全杨倩无缘巴黎奥运校方回应护栏损坏小学生课间坠楼房客欠租失踪 房东直发愁专家建议不必谈骨泥色变王树国卸任西安交大校长 师生送别手机成瘾是影响睡眠质量重要因素国产伟哥去年销售近13亿阿根廷将发行1万与2万面值的纸币兔狲“狲大娘”因病死亡遭遇山火的松茸之乡“开封王婆”爆火:促成四五十对奥巴马现身唐宁街 黑色着装引猜测考生莫言也上北大硕士复试名单了德国打算提及普京时仅用姓名天水麻辣烫把捣辣椒大爷累坏了

两个鬼故事 XML地图 TXT地图 虚拟主机 SEO 网站制作 网站优化