The LM317 is a functionally similar element

The maximum input voltage is more than 30 volts, output voltage, current.

The LM317 has three pins, one input, one output, and one voltage regulation. The input pin is connected to the positive voltage, the output pin is connected to the load, one pin of the voltage regulation pin is connected to the resistor (about 200) at the output pin, the other is connected to the adjustable resistor (a few k) to the ground, and the input and output pins are connected to the ground to the filter capacitor.

Second, the application of LM317.

LM317 is an easy-to-use and widely used integrated regulator with variable output voltage.

There are many models of the 317 series regulators: such as LM317HVH, W317L, etc. Electronics enthusiasts often use the 317 regulator block to make regulated power supplies with variable output voltage.

The output voltage of a regulated power supply can be calculated using the following formula, vo=. Just from the formula itself, the resistance values of R1 and R2 can be set arbitrarily. However, as a formula for calculating the output voltage of a regulated power supply, the resistance values of R1 and R2 cannot be set arbitrarily.

First of all, the output voltage change range of the 317 regulator block is VO = 317 regulator block with high output voltage, such as LM317HVA, LM317HVK, etc., and the output voltage change range is VO=, so the ratio range of R2 R1 can only be 0—.

Secondly, the 317 regulator block has a minimum stable working current, some data are called the minimum output current, and some data are called the minimum discharge current. The value of the minimum stable operating current is generally . Due to the different manufacturers and models of 317 regulator blocks, its minimum stable working current is also different, but generally not greater than 5mA.

1. Principle:The maximum input voltage is more than 30 volts, the output voltage and current have three pins, one input and one output and one voltage regulation, the input pin input positive voltage, the output pin is connected to the load, one pin of the voltage regulation pin is connected to the resistor (about 200) at the output pin, the other is connected to the adjustable resistor (a few k) to the ground, and the input and output pins are connected to the ground to be connected to the filter capacitor.

2. Application:The output voltage of the regulated power supply can be calculated by the following formula, vo=, from the formula, the resistance value of R1 and R2 can be set at will, and as the output voltage calculation formula of the regulated power supply, the resistance value of R1 and R2 cannot be set at will.

Normally, the LM117 LM317 does not require an external capacitor unless the input filter capacitor is more than 6 inches (about 15 cm) from the input of the LM117 LM317. The transient response can be changed by using the output capacitor, and the filter capacitor can be used on the adjustment side to obtain a much higher ripple rejection ratio than a standard three-terminal regulator.

Main parameters: 1. Output voltage: DC;

2. Output current:

3. The chip has overheating, overcurrent and short-circuit protection circuits inside;

4. Maximum input-output voltage difference: 40V DC, 5. Minimum input-output voltage difference: 3V DC;

6. Ambient temperature: -10-+85.

7. Storage environment temperature: -65-+150.

LM317 working principle: LM317 has the same input voltage of more than 30 volts, and the output voltage and current should be paid attention to when using it. Pay attention to heat dissipation.

The LM317 has three pins. One input, one output, one voltage regulation. The input pin is connected to the positive voltage, the output pin is connected to the load, one pin of the voltage regulation pin is connected to the resistor (about 200) at the output pin, and the other is connected to the adjustable resistor (a few k) to the ground.

The input and output pins are connected to ground with filter capacitors.

Hello, I'm glad to answer that the LM312T is an adjustable 3-terminal positive voltage regulator that can provide more than ampere voltage ranges from volts to 37 volts. This regulator is very easy to use and requires only a positive external resistor from the two-mode core to set the output voltage. Hope mine can help you!

Thank you! 

First, the working principle is different:

1. The use of LM117 is very simple, only two external resistors are needed to set the output voltage. In addition, it has better linear regulation and load regulation than standard fixed regulators. LM117 has built-in overload protection, safety zone protection and other protection circuits.

2. Usually the LM117 does not need an external capacitor, unless the connection between the input filter capacitor and the input terminal of the LM117 exceeds 15 cm. The transient response can be altered by using output capacitors. Using a filter capacitor on the adjustment side can achieve a much higher ripple rejection ratio than a standard regulator.

3. LM317 is one of the most widely used power integrated circuits, which not only has the simplest form of fixed three-terminal voltage regulator circuit, but also has the characteristics of adjustable output voltage.

4. In addition, it also has the advantages of wide voltage regulation range, good voltage stabilization performance, low noise and high ripple suppression ratio. The LM317 is an adjustable 3-terminal positive voltage regulator capable of delivering more than amperes over the output voltage range up to 37 volts, making it very easy to use.

Second, the load current and voltage are different

1. LM337 is a linear voltage regulator integrated circuit with adjustable output at three terminals. The output voltage range of the LM117 is up to 37V, and the load current is maximum.

2. LM117 can be used in many special ways. For example, levitating the regulator to a higher voltage can be used to regulate voltages up to hundreds of volts, as long as the input and output voltage difference does not exceed the limit of LM117.

3. Of course, it is necessary to avoid short circuit at the output end. The adjustment termination can also be connected to a programmable voltage for a programmable power output.

LM317 internal schematic (**It will take a while to see).

Working principle of three-terminal variable regulator tube:

1. Schematic diagram of LM317 three-terminal regulator tube:

2. Working principle: The output voltage of LM317 (that is, the output voltage of the regulated power supply) U0 is the sum of the two voltages, that is, the voltage between the two points of A and B and the voltage added to R2, and IR2 is actually the sum of the two currents, UR1 is a constant voltage, and R1 is a fixed resistance, so IR1 is a constant current. The other way is the current ID flowing out of the adjustment end of the LM317, and its value is basically constant when the LM317 is working stably.

Adjust R2, then, UR2=R*IR2 is variable with R2, and it can be seen that the output voltage can be adjusted by R2. In addition, LM317 has built-in protection functions and stable and reliable operation.

3. There are many varieties of three-terminal adjustable output regulator tubes, including positive output series and corresponding negative output series, and the working principle is similar.

The LM317 is an adjustable 3-terminal positive voltage regulator capable of delivering more than amperes over the output voltage range up to 37 volts. The output voltage of a regulated power supply can be calculated using the following formula, vo=. The difference with the LM78 and LM79 series is that the size of the regulated voltage can be set, while the stable voltage of the latter is fixed.

The LM317 is internally divided into a voltage stabilization section to provide a reference power supply, and a rear stage is amplified by current to provide sufficient power output.

The pinout of the LM317 is shown in the attached figure, and the pinout of the LM337 is the pinout of the LM337 when the input and output are swapped in the figure.

It's the same, 1 pin adjustment, 2 pin output, 3 pin input.