The Astable multivibrator circuit has no stable state. With no external signal applied, the internal transistors alternately switch from cutoff to saturation at a frequency determined by the RC time constants of the coupling circuits. So an Astable multivibrator is a square-wave oscillator with a oscillation frequency dependent on the value of the
Click here to download the full size of the above Circuit.
resistor and capacitors used in the circuit. The basic Astable Multivibrator circuit is shown below; however the description of the circuit operation is provided on the 555 Astable Circuit page. This circuit arrangement allows for independent charge and discharge times by forcing the capacitor [C1] charging through R1 and R4 [potentiometer] and the discharging current through R2 and R3 [potentiometer]. The diodes [D1 and D2] control the flow of current through the individual resistors; however both resistor paths use the same capacitor [C1]. In this case potentiometers are added to the circuit to allow for adjustment of the resistance in the timing path. However the potentiometers are not required and could be replaced with fixed resistors to control the charge and discharge times of the capacitor. Except for the addition of the potentiometers and the separate current paths created by the individual diodes, this circuit functions just like an Astable Multivibrator. The circuit could be simplified further by replacing the two variable resistors [R3 & R4] with a single variable resistor. The two end of the resistor would be connected to each of the diodes and the center tap would connect to pin 2 of the 555. The only issue with using one potentiometer is that the pulse widths are fixed together. So that as one period is increased [or decreased] the other period is decreased [or increased]. In addition a 50% Duty Cycle...
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: