The circuit illustrated produces a clean sine wave signal ideal for audio testing, or wherever a good-quality sine voltage source is required. It uses one integrated circuit which is a widely-available dual operational amplifier, the Texas Instruments TL072CP. The values shown provide an output frequency of about 1000 Hertz. This frequency may be
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varied over a wide range, using the equation shown in the schematic. Frequency is almost exclusively determined by the twin-T network in U1A`s feedback loop, provided that the gain-bandwidth product and slew rate specifications for the op amp are sufficiently high. For frequencies exceeding 10kHz, an faster op-amp in the U1A position is recommended. The oscillator`s frequency-selective twin-T network, C1, C2, C3, R1, R2, and R3, is in the negative feedback path of the operational amplifier. U1A`s positive-input to output transfer function is a notch filter with a frequency and depth determined by those components` values, with zero degrees of phase shift at the notch frequency. The twin-T network characteristics are defined by these equations: The positive feedback required for oscillation is provided by R4. Transistor Q1 is part of an automatic gain control (AGC) servo that regulates U1A`s positive feedback to keep the sine wave output at a consistent amplitude. The circuit will oscillate at the notch frequency when Q1`s emitter-to-collector resistance (Rec) is: U1B and its associated components complete the servo. The series-connected diodes provide negative peak-level detection of the sine wave voltage and also determine the amplitude of the output. Q1 is operated close to maximum conduction, so the small voltage from its emitter to collector contributes negligible distortion to the sine wave. The 0. 1uF integrating...
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....
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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....
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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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