Aideepen | LM317 Power Supply Adjustable Voltage Regulation Module Digital Display With Short Circuit Protection

Features:1. The adjustable power supply circuit using the LM317 three-terminal adjustable voltage regulator IC is simple and reliable in performance.2. The LM317 current-expansion circuit module, by connecting an external high-power PNP transistor (TIP36), enables the LM317 to deliver up to 3A output current (requires a larger heat sink for the power transistor) and includes short-circuit protection.3. For small voltage drops and currents below 2A, the onboard heat sink suffices. If current exceeds 2A with high input/output levels, replace the TIP36 PNP transistor with a larger heat sink.4. The module operates as a series voltage regulator circuit, adjusting the output voltage by modulating the conduction level of its internal switching transistor.5. Features short-circuit protection; brief output shorts will not damage components. Includes input rectification circuit for non-polarity input.Product Specifications:DC Input: DC 5-30VAC Input: AC 3.5-21VDC Output: DC 1.25-27VMinimum Input-Output Voltage Drop: 3V (Step-down regulation; output is always lower than input)Maximum Current: 3APCB Dimensions: 88mm (L) × 47mm (W)Product Dimensions: 88mm (L) × 65mm (W) × 55mm (H)Circuit Principle:The TIP36 transistor and resistor R4 form a current-limiting circuit. Resistor R5 serves as a sink resistor, ensuring the operating current within the LM317 circuit does not exceed the base current of the TIP36 transistor. Resistor R4 functions as a short-circuit protection resistor. During a short circuit, when current exceeds the limit value, the voltage drop across R4 increases, reducing the emitter-base voltage of the TIP36. This prevents the TIP36 from conducting. The current flowing through resistor R5 enters the LM317's input terminal. If the current exceeds the LM317's maximum output current, its internal overcurrent and overheat protection circuits activate. This automatically reduces the LM317's output current, achieving short-circuit protection.Product List:Kit 1:LM317 Power Regulator Module DIY Kit (Unassembled, Requires Self-Soldering)Kit Contents (Shipping List):PCB Board * 15.1K Resistor * 1120Ω Resistor * 11N4007 Diode * 12W 22Ω Resistor * 15W 0.22Ω Resistor * 15mm Red LED * 1104 Ceramic Capacitors * 225V 10μF Capacitor * 150V 470μF Capacitor * 150V 1000μF Capacitor * 15K Fixed-Leg Potentiometer * 1Potentiometer Cap * 1KF301-2P Terminal Block * 2M38 Screws * 3LM317 1231625 Heat Sink 1TIP36 1504518 Heat Sink * 1M36 Self-Tapping Screws 3Kit Two:1 x Pre-Assembled LM317 Power Regulator Module (Fully soldered, ready to use upon receipt)