This is a motor speed control circuit that allows safe and easy control of 115VAC `universal motors` like drill motors, blender motors, other power tools, etc. The motor is controlled directly by a triac-diac component that is found in variable-speed universal motor devices (such as electric drills. ) The component will not allow current to flow th
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rough the motor until the R-C network charges to a certain level. In this case the capacitance is fixed, but the resistance is determined by a CdS photoresistor. A standard LED is optically coupled to the CdS photoresistor, and the LED is controlled by a 555 astable circuit. The duty cycle of the 555 output waveform will determine the average amount of light falling on the CdS photoresistor, and thus the CdS resistance, and thus the current flowing through the motor. For best operation, the 555 output frequency should be much higher than the mains AC frequency (ie 60 Hz). A good value for the 555 frequency would be about 5 KHz. The 555 control voltage is set by an opamp circuit (LM324) that amplifies the difference between a user-set voltage and a voltage generated by a small motor whose shaft is coupled to the main motor being controlled. The small motor`s function is to generate a DC voltage that is proportional to shaft speed. Its value is amplified and integrated by the opamp circuit for programmatic proportional and integral control. The 555 serves as a high-current pulse driver for the LED, taking an analog control signal and allowing some control of the pulse rate and height via the R-C timing network and current-limiting resistor.
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.....
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