This circuit uses a dual operational amplifier (TL082) to form a voltage-controlled oscillator (VCO). With the component values shown, the output-frequency range is 100 Hz to 10 kHz when the input control voltage is between 0. 05 and 10 V. (View) The input pulse is fed into the sample-and-hold amplifier (an inexpensive AD582), as well as the compa
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rator U3. The SHA`s output also is fed into the comparator. If the input pulse is higher in am-plitude than the SHA`s output, the comparator output goes low and the 4538 one-shot produces a l0-ps pulse that is fed back to cause the SHA to sample and then hold the voltage. Subsequent input voltages that are less than the held value won`t cause the one-shot to fire again. Gates U4A and U4B are used to inhibit the sampling when necessary. Gates U4C and U4D, at the one-shot`s output, can force the AD 582 into the sample mode. This feature is useful to reset the output to zero by forcing a sample when the input to the AD582 is zero. The polarity of the peak-hold circuit can be easily changed from positive-to-negative peak hold by reversing the inputs of the comparator. (View) This regulator uses the drop across R3 to sense current draw, turning on Q2, removing drive from Q1, and lowering the output voltage. Limiting occurs when Q2 has 0. 65 V across the base-emitter junction. This circuit has foldback characteristics as seen from the figure. (View) The circuit has a duty-cycle generator that will produce an output varytng from fully off to fully on and pulses of any duty cycle in between the two extremes. This method of operation is called PWM (pulse zuidth moduhtion) The circuit can be fed fromany dc supply source of between 10 to 15 V Half of an LM556 dual oscillator timer and U2 a(1/4 of an LM339 quad comparator) combine to...
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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