As its name indicates it has one stable state and it switches to unstable state for a predetermined time period T when it istriggered. The time period T is determined by the RC time constant in the circuit. Monostable mode of 555 Timer is commonly used for generating Pulse Width Modulated ( PWM ) waves. This is the circuit diagram of 555 Timer wired in Monostable mode.
Click here to download the full size of the above Circuit.
8th pin and 1st pin of the 555 timer are used to givenpowerVcc and Ground respectively. 4th pin is the Reset pin of 555 Timer, which is active low so it is connected to Vcc to avoid accidental resets. 5th pin is the Control Voltage pin used to provide external reference voltage to internal comparators. Since it is not used here, it is grounded via a capacitor C` (0. 01 µF) to avoid high frequency noises. When a negative trigger is applied on the Trigger input of 555, output goes high and capacitor starts charging through resistor R. When the capacitor voltage becomes greater than 2/3 Vcc, ouput goes low and capacitor starts discharging through the Discharge pin of 555 Timer. Time period of the unstable state is given the tye expression, T = 1. 1RC. When a negative trigger is applied to the Trigger pin of 555 Timer, output of lower comparator will become HIGH and output of upper comparator will be LOW, since the capacitor voltage is zero. This makes the output HIGH. After the negative trigger, output of lower comparator becomes LOW and that of upper comparator remains LOW. Since both inputs of the SR Flip Flop are LOW, output will not change, so the output is HIGH. When the capacitor voltage will become greater than 2/3 Vcc, output of upper comparator becomes HIGH and that of lower comparator remains LOW, so the output becomes LOW.
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: