LM Fluid Detector. The is a monolithic bipolar integrated circuit designed for use in fluid detection systems The circuit is ideal for detecting the presence. LM datasheet, LM circuit, LM data sheet: NSC – Fluid Detector, alldatasheet, datasheet, Datasheet search site for Electronic Components and. LM Datasheet, LM PDF, LM Data sheet, LM manual, LM pdf, LM, datenblatt, Electronics LM, alldatasheet, free, datasheet.

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Pin 9 of the IC can be used to solve this problem. Manufactured by National Semiconductors, the LM can detect the presence or absence of polar fluids. For non metal tanks fix a small metal contactor at its bottom level and ground it. With the give value of C1 the frequency will be around 6KHz. Level indicator using external reference resistor. The load connected through the relay whether pump, lamp, alarm, solenoid valve or anything is driven.

You may see the circuit if you are interested. Capacitor Ct sets the frequency of the internal oscillator.

LM Datasheet(PDF) – National Semiconductor (TI)

You may also like: The circuit diagram of a liquid level indicator using loud speaker at llm1830 output is shown below. Low liquid level warning audio. Please refer to the second circuit above. You have to connect the tweeter between Pin No12 and Vcc through suitable resistance.

A method for activating a relay when the liquid level exceeds a predetermined level is shown here.

LM1830 Datasheet PDF

The tank must be made of metal and it should dattasheet properly grounded. Hi Rohit Pin No 5 is oscillator out put for external reference resistance.


Hai, Can it be used for Water level indicator in a Over head Tank. Achei fantastico o site. The load that is the relay is connected at the collector of Q1. Loud speakers can be driven only by using AC signals and a DC signal will not produce any sound out of the speaker. A capacitor connected from this pin to ground will keep the internal output transistor steadily ON whenever the probe resistance goes higher than the reference resistor.

The circuit of a low liquid level indicator with LED is shown above. The circuit is similar to the first circuit except that the LED is replaced by a loud speaker and the load current limiting resistor is changed from 1. When the probe to ground resistance goes above the R ref the oscillator output is coupled to the lm180 of the internal output transistor making it conducting.

In such cases there is dataaheet to avoid the internal reference resistor and an external reference resistor of your choice Rx in the circuit can be employed. Atenciosamente… Washington Souza Gomes. Hi Challa it is meant for normal water, hence can be used for our domestic use dataaheet control over head tank water level.

The probe used here can be any metal rod with size and shape of your choice. The LED connected to the collector between pin 12 and Vcc is driven.

Some time there may be situations when the fluid resistance probe to ground llm1830 not match with the 13K internal reference resistor. How could I use this circuit to control the Digital input on a microcontroller? Liquid level indicator admin October 12, 11 Comments.


Previous post Next post. DC voltage is required for driving the relay and AC voltage cannot be used here just like what we did in the case of LED and speaker. The probe must be placed at the level you want to monitor. The oscillators output is directly available at pin 5 and the Rx connects the oscillator output to the probe through the blocking capacitor.

LM1830 PDF Datasheet浏览和下载

The circuit detects the fluid level by comparing the probe to ground resistance with the internal reference resistor R ref. LM based liquid level indicator circuit. Low liquid level indicator LED. When the probe is not touching the water it equal to datasbeet open circuit situation and surely the probe resistance will be many M ohms and it is greater than the R ref 13K. Circuits based on this IC requires minimum number of external components and AC signal is passed through the sensing probe immersed in the fluid.

The internal transistor will be switched ON and Q1 dwtasheet base is connected to the collector of the internal transistor will be in OFF condition keeping the relay inactive. Resistor R3 limits the collector current of the internal transistor while datasjeet R4 provides protection to the IC from transients.