34results about How to "Small current change" patented technology

The invention discloses a method for removing and preventing wax of a mechanical recovery well by a microorganism wax removal and prevention composite bactericide. In the method, the microorganism composite bactericide is injected into a well bottom, and the concentration of the composite bactericide in well bottom liquid is not lower than 100mg / L, and is up to 50,000 mg / L; and an agent adding cycle is 10 to 28 days to ensure that the wax content of crude oil is reduced until the standard is met. Through a wax removal and prevention experiment of eight wells on which wax can be precipitated easily, compared with a method for removing and preventing wax by using a chemical wax removal and prevention agent, the method has the advantages that: the using amount of the microorganism wax removal and prevention agent is recued by more than 40 percent, the cost is saved by 20 to 50 percent, the agent adding cycle is more than two times the conventional agent adding cycle, and the economic benefit is obvious; moreover, during experiment, current of the mechanical recovery well changes slightly, and the current is in a stable state basically, and the effect is better or equal to that of the chemical wax removal and prevention agent. Therefore, the method has the advantages of low environmental pollution, low cost, long action period, high economic benefit and wide application range, plays an important role in the wax removal and prevention of the field of oil exploitation, and has wide application prospect.

The present invention provides a drive circuit and method for a sending end, including: a calibration control unit that generates a calibration control signal that varies with the process, power supply voltage or temperature; a current calibration unit that generates a calibration current based on the calibration control signal; generates a bias based on the calibration current A bias voltage generation unit for the voltage; an output stage drive unit for amplifying the output signal based on the bias voltage; and an impedance matching unit for adjusting the output impedance based on the calibration control signal. Generate a calibration control signal; generate a calibration current based on the calibration control signal to obtain a bias voltage; amplify the signal to be output under the action of the bias voltage, and obtain a stable output signal through impedance matching. The present invention effectively reduces the current and resistance changes caused by process, power supply voltage and temperature changes, meets the requirements of the HDMI2.0 protocol for output voltage amplitude changes at the sending end, achieves better impedance matching effects, and effectively improves signal transmission quality .

A variable transconductance circuit is provided in the invention. The variable transconductance circuit includes: a voltage-current conversion circuit for outputting a current signal linear with an input voltage signal (Vi); first and second MOS transistors (M1, M2) for converting the current signal received to a square-root compressed voltage signal; and third and fourth MOS transistors (M3, M4) for converting the square-root compressed voltage signal to a linear current signal. A bias current (Ia) at the first and the second MOS transistors (M1, M2) and a bias current (Ib) at the third and the fourth MOS transistors (M3, M4) are varied to control gm, thereby achieving about 20-times variation with a low power supply voltage of about 3V within one circuit to solve a problem that increase in power consumption and mounting circuit area.

A metal detector for a belt conveyer applied to the fields of coal, metallurgy, electricity, mine and the like comprises sensors, an oscillator, a high amplification circuit, a detection circuit, a low amplification circuit and an actuator. Two sensors L1 and L2 are arranged. The sensor L1 is sleeved on a belt, and the sensor L2 is placed below a conveying belt. A signal of the sensor L1 passes through an amplification channel and then enters a positive and negative phase detection circuit consisting of diodes D21 and D22. The detected signal is divided into two paths and then respectively enters amplifiers IC8 and IC9. The amplifier IC8 outputs the signal to an amplifier IC10 to drive the actuator. The amplifier IC9 outputs the signal to control the grid of a field effect tube V9. The field effect tube V9 and a resistor R30 which divide the voltage output the voltage to control the input voltage of the amplifier IC10. A signal of the sensor L2 passes through an amplification channel and then is outputted through an amplifier IC11 to drive a field effect tube V10. The field effect tube V10 and the resistor R30, which divide the voltage, control the input voltage of the amplifier IC10. The metal detector avoids the interference caused by reinforcing a wire connector in the conveying belt and the interference due to variation of magnetic inductivity in the process of conveying ore materials.