discount 70% in 2018-09-21 to 2018-09-23
price: USD$ 14.00
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LM317 adjustable DC power supply board, increasing the radiator for large adjustment potentiometer, AC / DC
Can input, the input voltage range: 3-40V, with overload protection, can be connected to the load below 1.5A,
1.25V-37V continuously adjustable, wide application range.
The plate core components: original large chip chip adjustable voltage LM317, can load 1.5A below, can be AC or DC input voltage, maximum input voltage: 3-40V AC / DC, DC output voltage range: 1.25V-37V continuously adjustable; increase the load protection circuit, protection function to load up. It is widely used in rare dc.
The LM317T produced with adjustable power supply, often due to poor contact potentiometer, the output voltage increases and burning load. If the increase of a transistor, under normal circumstances,TriodeThe base potential is 0,TriodeStop, no effect on the circuit; and when the bad contact potentiometer,TriodeThe base potential rise, when rose to 0.7v,TriodeConduction will adjust terminal voltage and decrease of LM317T,The output voltage is reduced, thus protecting the load up. We do experiments with a small 3.8V bulb, such as removing the triode, disconnect the potentiometer line of the center, small bulbs to burn out, measuring the output voltage up to 21V. But with a triode, a small lamp brightness decreases, the output voltage of LM317T is only 2V, which effectively protects the load.
The introduction of LM117/LM317:
LM117/LM317 is a National Semiconductor Corporation Ns of three terminal adjustable positive voltage regulator integrated circuit, China and the world's major integrated circuit manufacturers have similar products available for use, is widely used as a kind of integrated voltage regulator series.
And the output voltage range of LM117/LM317 is l.25V to 37V. It is easy to use and require only two external resistors to set the output voltage. In addition to its linear regulation and load regulation are better than standard fixed regulators. LM117/LM317 has a built-in overload protection, safety protection and other protection circuits.
Usually, LM117/LM317 does not require an external capacitor, unless the input filter capacitor to the LM117/LM317 input line more than 6 inches (about 15 cm). The use of the output capacitor can change the transient response. Adjust the end using the filter capacitor than the standard three terminal regulator is much higher than the ripple suppression.
LMll7/LM317 has a lot of special usage. Such as the adjustment of the suspension to the end of a high voltage, can be used to adjust the voltage up to hundreds of volts, as long as the limit of the input and output pressure of not more than LM117/LM317 on the line. Avoid short circuiting the output. Can also adjust the terminal to a programmable voltage, the power output can be programmed.
The input than output of high voltage 2V, or not. The input voltage can not exceed the maximum 40V. The output current is less than 1A. Input l2V, the maximum output is about 10V.
ReadingIs due to the internal LM317 linear regulator, so the power consumption is relatively large. When the input voltage difference is relatively large and the output current is relatively large, 317 large power consumption do not pay attention to. General with radiator after power is less than 20W. So the pressure is recommendedStep voltage。