A 1 A Schottky barrier rectifier in the axial DO-41 package, chosen wherever a low forward drop and fast recovery matter. Its forward voltage is only about 0.6 V at 1 A (versus ~1.1 V for a silicon 1N4007) and it switches almost instantly, so it wastes less power and works past line frequency. That makes it the default for switch-mode freewheeling, low-voltage rectification, reverse-polarity protection, and OR-ing supplies, at the cost of a higher reverse leakage than silicon. It blocks 40 V reverse; the banded end is the cathode (pin 1).

Pinout

Pin	Name	Type	Function
1	K	passive	Cathode terminal, identified by the cathode band on the package body. Rated for 40V peak repetitive reverse voltage (VRRM) with 1.0mA typical reverse leakage @ 25°C.
2	A	passive	Anode terminal. Forward current flows from anode to cathode with VFM = 0.60V @ IF = 1.0A (0.90V @ IF = 3.0A).

Key specifications

Parameter	Value
Type	Schottky barrier rectifier
Reverse voltage (VRRM)	40 V
Forward current (IF avg)	1 A
Forward voltage (VF)	~0.6 V at 1 A
Surge current (IFSM)	25 A
Recovery	fast (Schottky)
Marking	band = cathode (pin 1)
Package	DO-41 (axial THT)

Ordering variants

1N5819-T (DO-41)
1N5819-B (DO-41, bulk)

CAD (KiCad official)

Symbol: Diode:1N5819
Footprint: Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal
3D model: DO-41 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Diodes Incorporated datasheet (5 pp, sha256 973674801eaa0c18, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF