Product Features:
1.LM317 three-terminal adjustable voltage regulator IC to do adjustable voltage regulator power supply circuit is simple, reliable performance.
2.LM317 current expansion circuit module, through the external high-power PNP-type (TIP36) transistor, you can make the LM317 output current up to 3A (need to increase the heat sink of the power tube), and with short-circuit protection.
3. In the case of small differential pressure, current less than 2A, the board comes with a heat sink can meet the heat dissipation requirements, if the current is greater than 2A at the same time as the input and output is larger, please replace the high-power PNP transistor TIP36 with a larger heat sink.
4. The working principle of the module is equivalent to a series voltage regulator circuit, by adjusting the degree of conduction of the internal switching tube to adjust the output voltage.
5. With short-circuit protection, the output of a short time short circuit will not burn the device, the input with rectifier circuit, can be input without polarity.
1.LM317 three-terminal adjustable voltage regulator IC to do adjustable voltage regulator power supply circuit is simple, reliable performance.
2.LM317 current expansion circuit module, through the external high-power PNP-type (TIP36) transistor, you can make the LM317 output current up to 3A (need to increase the heat sink of the power tube), and with short-circuit protection.
3. In the case of small differential pressure, current less than 2A, the board comes with a heat sink can meet the heat dissipation requirements, if the current is greater than 2A at the same time as the input and output is larger, please replace the high-power PNP transistor TIP36 with a larger heat sink.
4. The working principle of the module is equivalent to a series voltage regulator circuit, by adjusting the degree of conduction of the internal switching tube to adjust the output voltage.
5. With short-circuit protection, the output of a short time short circuit will not burn the device, the input with rectifier circuit, can be input without polarity.
Product parameters:
DC input: DC5-30V
AC input: AC 3.5-21V
Output DC: DC 1.25-27V
Minimum voltage difference between input and output: 3V (buck regulator, output is always less than input)
Maximum current: 3A
Circuit board size: 88mm long × 47mm wide
Product size: 88mm long * 65mm wide * 55mm high
Circuit working principle:
TIP36 transistor and resistor R4 form a current expansion circuit. Resistor R5 is a current drain resistor, its role is to make the internal circuit of LM317
LM317 internal circuit operating current does not exceed the base current of the TIP36 transistor. Resistor R4 is a short-circuit protection resistor, when the short-circuit, the current exceeds the limit value, the voltage drop on resistor R4 increases, so that the emitter junction voltage of the TIP36 decreases, resulting in the TIP36 is not hungry to conduct. The current copper tube R5 flows into the input of LM317, as the current exceeds the maximum output current of LM317, at this time, the internal overcurrent protection and overheating protection circuit of LM317 will work to make the output current of LM317 reduce automatically, so as to achieve the short-circuit protection function.
DIY list:
LM317 power supply regulator module DIY loose parts kit (not welded, need to weld yourself)
Kit list:
PCB board * 1
5.1K resistor * 1
120Ohm resistor * 1
1N4007 diode * 1
2W 22 ohm resistor * 1
5W 0.22 ohm resistor * 1
5MM LED red hair red * 1
104 Monolithic Capacitor *2
25V10UF Capacitor * 1
50V470UF Capacitor *1
50V1000UF Capacitor *1
5K potentiometer with fixed feet * 1
Potentiometer cap *1
KF301-2P terminal block * 2
M3*8 screw * 3
LM317 *1
23*16*25 Heat Sink *1
TIP36 *1
50*45*18 heat sink * 1
M3*6 self-tapping screws * 3
Package include: finished board or DIY kits, according buyer choose