Pinout

Linear voltage regulator (TO-220, e.g. 7805) pinout

Pins

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	≈ 2 V typ at 1 A
Output current	Up to 1.5 A with adequate heatsinking
Quiescent current	≈ 4–5 mA typ, 8 mA max
Protection	Internal current limit, thermal shutdown, safe-area protection
Recommended capacitors	0.33 µF on input, 0.1 µF on output (datasheet reference circuit)
Thermal note	Dissipation = (Vin − Vout) × I; above ≈ 1 W fit a heatsink
Operating junction temperature	0–125 °C (commercial grade)
Package	TO-220 (also D2PAK, DPAK)

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%
LM2596 buck converter moduleConverter 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)
CAN bus (2-wire differential)Signals: CAN_H, CAN_L + common GND; Topology: Linear multi-drop bus, multi-master with arbitration; Duplex: Half duplex
SD card (SPI mode)Contacts: 9 (SD), 8 (microSD); Supply: 2.7–3.6 V; Logic level: 3.3 V, not 5 V tolerant
SWD debug (2-wire, ARM Cortex-M)Signals: SWDIO, SWCLK + GND, VTref; Optional: nRESET, SWO trace; Topology: Point-to-point (one probe, one target)
JTAG (4-wire debug, common subset)Standard: IEEE 1149.1; Signals: TCK, TMS, TDI, TDO (+ optional TRST); Topology: Daisy chain on TDI → TDO, TCK / TMS shared