Working principle is different: The LM117 is very simple to use, only two external resistors are needed to set the output voltage. In addition, its linear adjustment rate and load adjustment rate are better than standard fixed regulators. The LM117 has built-in overload protection, safety zone protection and other protection circuits.
is different. The lm317 has three endsAdjustable positive regulator, output current 5A, output voltage 2V-37V. The lm337 is a three-terminal adjustable negative regulator with an output current of 5A and an output voltage of -2V to -37V.
LM317 is a positive output, and LM337 is a negative output.
Therefore, LM117, LM217, LM317 are negative voltage three-terminal regulators, while LM137, LM237, LM337 are positive voltage three-terminal regulators, and the "1", "2" and "3" in front of them respectively indicate the operating temperature.
LM337 Yesp>2, the power transformer can choose a 25W transformer with an output voltage of 15V, which has a sub-side output voltage peak of 189V when the grid voltage falls by 10%, and the voltage after bridge rectification and filtering is about 17V.
3, the role of adjustable three-terminal voltage regulator LM317 V1 and V2 is: when the output short circuit, the voltage on C2 is discharged by V2, so as to achieve the purpose of reverse bias protection. In addition, when the input is short-circuited, the voltage stored on components such as C3 is drained through V1 to prevent the internal regulator from reverting. C2 is used to improve the ripple suppression ability of IC.
A voltage regulator chip is an electronic component that can stably adjust the input voltage to a specific output voltage. The way it works is that when the input voltage changes, the regulator chip detects this change and adjusts the output voltage to keep it at a specific voltage level.
Voltage regulator is a power supply circuit or power supply device that can automatically adjust the output voltage, and its role is to stabilize the power supply voltage that fluctuates greatly and is not required by the electrical equipmentWithin the set value range, so that various circuits or electrical equipment can work normally under rated operating voltage.
Three-terminal voltage regulator A three-terminal voltage regulator is an electronic device that controls the output voltage by comparing the input voltage with the reference voltage. It usually consists of three parts: the input, the comparison circuit and the output.
LCM, interface converter, instrument, flashing light, product control circuit with clock display. Voltage regulator IC includes: DC/DC boost chip 5V, 3V, 3V, boost IC output voltage adjustable, LDO voltage regulator 6206 series, with enable terminal systemColumn LDO, low voltage detection reset IC, backlight driver chip, LED driver IC, MOS tube, etc.
There is also an amplifier inside the LM723 chip that amplifies the output signal of the comparator and outputs it to the control circuit. According to the output signal of the amplifier, the control circuit controls the regulating circuit, thereby adjusting the output voltage to keep it at the level of the reference voltage.
1, first use the transformer to reduce the voltage of 220V to the appropriate value. Then through the rectifier circuit, the sine wave is changed into a more stable DC voltage. Through the filter and voltage regulator circuit, the voltage after rectification is filtered and regulated, and finally the DC power supply that meets the requirements is obtained.
2, with LM317, it can be adjusted to the voltage you need, the output current is also large. I drew a picture for a netizen before, and then posted it, you have a look, the input in the figure can be changed to 32V you use.
3Depending on the working voltage range of the chip, it is generally lower than the maximum voltage, it is recommended not to use 7812, because the chip has been in the maximum voltage 12V working state, will shorten the service life of the chip, or reduce the chip security.
4, the following is a transformer center tap for the ground of the ±12V power supply circuit (7812 positive voltage three-terminal regulator block and 7912 negative voltage three-terminal regulator block),
5, you can expand the flow through 7805 and 7812 as required. The resistance is 1 ohm and 1 watt, and the capacitor and triode are selected according to the required currentTake, triode need to install heat sink, 12V is the same.