Pinout

LM2596 buck converter module pinout

Pins

IN+ / IN− (4.5–40V DC in)
OUT+ / OUT− (1.25–37V out, always below Vin by ≥1.5V)
Multi-turn pot sets the output — screw counter-clockwise to lower it, and SET IT BEFORE wiring the load
~2A continuous (3A peak with a heatsink); efficiency ~80–90%

Converter IC	LM2596 (step-down switching regulator)
Input voltage	4.5–40 V
Output voltage	1.23–37 V adjustable (needs ≈ 1.5 V or more of headroom)
Output current	IC rated 3 A; ≈ 2 A continuous on a typical module without extra heatsinking
Switching frequency	150 kHz
Efficiency	≈ 80–90% depending on input/output voltages and load
Quiescent current	≈ 5 mA typ (IC)
Protection	Current limit and thermal shutdown (IC)
Adjustment	Multi-turn trimmer potentiometer

Linear voltage regulator (TO-220, e.g. 7805)Output voltage: 5 V ±4% (7805); 78xx family also 6, 8, 9, 12, 15, 18, 24 V; Input voltage: ≈ 7–25 V in use; 35 V absolute max (5–18 V versions); Dropout:…
LM317 adjustable regulator (TO-220)Output voltage: 1.25–37 V, set by two resistors; Output formula: Vout = 1.25 V × (1 + R2/R1); R1 typically 240 Ω; Input–output differential: 3–40 V…
AMS1117 linear regulator (SOT-223)Output voltage: Fixed 1.5, 1.8, 2.5, 2.85, 3.3 or 5.0 V, or adjustable (1.25 V reference); Output current: 1 A; Dropout: ≈ 1.1 V typ, 1.3 V max at 1 A
TP4056 Li-ion charger moduleCharger IC: TP4056 (linear, constant current / constant voltage); Input voltage: 5 V nominal (4–8 V per the datasheet); Charge voltage: 4.2 V ±1%
PCF8574 I2C port expander (DIP-16)Supply voltage: 2.5–6 V; Interface: I2C, 100 kHz (standard mode); I2C address: PCF8574: 0x20–0x27; PCF8574A: 0x38–0x3F (set by A0–A2)
CD4017 decade counter (DIP-16)Logic family: CD4000 series CMOS; Supply voltage: 3–18 V; Max clock frequency: ≈ 5 MHz typ at 10 V (lower at 5 V)
ILI9341 TFT display (SPI, 2.4″)Controller: ILI9341; Resolution: 240 × 320 pixels; Colour depth: Up to 262K colours (18-bit); 16-bit RGB565 typical
N-channel MOSFET (TO-220, e.g. IRLZ44N)Example part: IRLZ44N (logic-level); Drain–source voltage: 55 V max; Drain current: 47 A max at 25 °C case (limited by heat in practice)