What Is the 1N4002G Rectifier Diode and How Is It Used?

Quick answer: The 1N4002G is a 1 A, 100 V glass-passivated rectifier diode in a DO-41 axial package. Use it for low-voltage AC-to-DC conversion, reverse-polarity protection, and freewheeling in 50/60 Hz circuits. It is not designed for 230 V mains or high-frequency switching.

(Last modified date: August 31, 2026)

In this guide, we break down how the 1N4002G operates as a rectifier, its key electrical specifications, the applications where it earns its place, how it compares with the rest of the 1N400xG series, and how to test it before it goes into a design.

Key Takeaways

The 1N4002G is a 100 V, 1 A general-purpose rectifier — a common choice for 48 V and lower line-fed DC rails.
Apply the same derating logic as the rest of the family: temperature, surge, and repetitive peak reverse voltage; see general-purpose rectifier selection.
Compare 1N4001G (50 V) and 1N4004G (400 V) when the rail voltage changes. The 1N4002G covers 100 V, 1 A rectification duties.

How Does the 1N4002G Operate as a Rectifier?

The 1N4002G conducts current in one direction when forward biased and blocks reverse voltage up to 100 V. In AC circuits, it allows only the positive (or negative, depending on orientation) half-cycle to pass, converting AC into pulsating DC. Its 1 A average current rating and 30 A surge capability make it ideal for low-power rectification in power supplies and protection applications.

In power electronics, the 1N4002G is commonly used as a single diode in half-wave rectifiers, as part of full-wave bridge configurations, or as a freewheeling / catch diode in inductive loads. Its glass passivation provides good stability and moisture resistance, while the DO-41 package allows easy through-hole mounting on PCBs or in chassis designs.

The diode’s relatively slow reverse recovery (~2 µs) means it is not suitable for high-frequency switching but is perfectly adequate for 50/60 Hz line rectification and low-frequency SMPS auxiliary circuits. When used in protection roles, the 1N4002G can clamp reverse polarity, limit voltage spikes, or provide a discharge path for inductive energy. Designers often pair it with resistors, capacitors, or TVS devices to form robust input protection stages. Good-Ark Electronics, as a major rectifier and discrete device manufacturer, offers 1N400xG series products with similar specifications, enabling designers to source reliable alternatives for these applications.

What Are the Key Electrical Specifications of the 1N4002G?

The 1N4002G provides 100 V peak repetitive reverse voltage, 1 A average forward current, 30 A peak surge current, approximately 1 V forward drop at 1 A, 5 µA reverse leakage at 100 V, and about 2 µs reverse recovery time. It operates from –55 °C to +150 °C junction temperature in a DO-41 glass package, making it suitable for general-purpose low-power rectification.

These parameters define how the device behaves in real circuits. The 100 V reverse voltage rating (VRRM) allows it to be used in circuits where the peak AC voltage does not exceed this limit, typically up to about 70 V RMS. The 1 A average current (IO) sets the continuous load limit, while the 30 A surge (IFSM) gives short-term headroom for start-up or fault conditions.

Forward voltage (VF) around 1 V at 1 A determines conduction loss and thermal design, and reverse leakage (IR) of a few microamps ensures minimal standby loss. Reverse recovery time (trr) of about 2 µs indicates the 1N4002G is a “standard recovery” diode, not a fast or ultrafast type. This makes it well matched to 50/60 Hz mains rectification and low-frequency switch-mode auxiliary windings, but unsuitable for high-frequency resonant converters or RF applications. Junction capacitance around 8–15 pF and thermal resistance about 50 °C/W further define its dynamic and thermal behavior in practical designs.

Parameter	Symbol	Typical Value	Condition
Peak Repetitive Reverse Voltage	VRRM	100 V	—
Average Forward Current	IO	1 A	TA = 75 °C
Peak Forward Surge Current	IFSM	30 A	One pulse
Forward Voltage	VF	~1.0 V	IF = 1 A
Reverse Leakage Current	IR	5 µA	VR = 100 V
Reverse Recovery Time	trr	~2 µs	—
Junction Capacitance	CJ	8–15 pF	VR = 4 V, 1 MHz
Max Junction Temperature	Tj	150 °C	—

Which Applications Are Best Suited for the 1N4002G?

The 1N4002G is ideal for 50/60 Hz AC-to-DC rectifiers, low-power SMPS auxiliary circuits, freewheeling diodes in inductive loads, reverse polarity protection, and voltage clamping in automotive, home appliance, and industrial power equipment. Its 1 A rating and 100 V blocking make it unfit for high-voltage mains or high-frequency switching, but perfect for general-purpose discrete rectification.

In consumer electronics, the 1N4002G appears in small wall-adapted power supplies, LED drivers, and battery chargers where the input voltage is limited and current demand is modest. In automotive electronics, it can be used for polarity protection at input terminals, as a clamp in sensor circuits, or as a freewheeling diode for low-power relays and actuators. Its glass-passivated structure and robust DO-41 package support environments with temperature variation and moderate humidity.

Industrial power equipment and instrumentation often use the 1N4002G in auxiliary rectifier stages, snubber circuits, and protection networks. For example, in a small switch-mode power supply, it may rectify an auxiliary winding to provide bias or feedback voltage. In motor control or EPS systems, it can safely discharge inductive energy when a coil is switched off. Good-Ark Electronics supplies a wide range of rectifier diodes and discrete power devices that can substitute or complement the 1N4002G in such applications, supported by a global sales and technical support network.

Why Choose a Glass-Passivated DO-41 Rectifier Like the 1N4002G?

Glass passivation gives the 1N4002G excellent stability, moisture resistance, and long-term reliability in demanding environments. The DO-41 axial package is simple, robust, and compatible with standard through-hole assembly, making it ideal for cost-effective, low-power rectifiers in power supplies, automotive, and industrial equipment where reliability and ease of integration are critical.

The glass envelope surrounding the silicon junction protects against contamination and humidity, reducing the risk of leakage or degradation over time. This is particularly important in applications exposed to temperature cycling, humidity, or mild chemical environments, such as automotive under-hood electronics or industrial control panels. The epoxy-molded variant with corrosion-resistant surfaces and solderable leads further enhances mechanical and environmental robustness.

From a design perspective, the DO-41 package is widely supported by PCB layouts, hand assembly, and automated insertion equipment. Its axial leads simplify routing and mechanical anchoring, and the polarity band clearly marks the cathode, reducing assembly errors. Compared with surface-mount alternatives, the 1N4002G’s through-hole form factor offers higher surge current handling and better thermal paths in some designs, albeit at the cost of a larger footprint and manual or hybrid assembly.

How Does the 1N4002G Compare to Other 1N400xG Series Diodes?

The 1N4002G is part of the 1N400xG family, differing mainly in reverse voltage rating: 1N4001G (50 V), 1N4002G (100 V), 1N4003G (200 V), up to 1N4007G (1000 V). All share 1 A average current, similar forward voltage, surge capability, and package. Designers select the 1N4002G when 100 V blocking is sufficient, balancing cost and performance for low- to medium-voltage applications.

This family allows designers to standardize on a single current rating and package while scaling voltage capability. For example, a 12 V DC system may only need 1N4001G or 1N4002G, whereas a 230 V AC mains rectifier typically requires 1N4004G–1N4007G. The 1N4002G is often chosen as a versatile middle option: enough voltage margin for 48 V systems, automotive 12/24 V circuits with transients, and some low-voltage industrial supplies, without the extra cost of higher-voltage variants.

Part Number	VRRM	Typical Application	When to Choose It
1N4001G	50 V	12 V logic rails, low-voltage polarity protection	Minimum voltage headroom is enough; lowest cost
1N4002G	100 V	24/48 V systems, automotive 12/24 V circuits with transients	100 V blocking covers the rail — the balance point of this article
1N4003G	200 V	110 V AC low-voltage mains rectification	Peak voltage exceeds 100 V but stays below 200 V
1N4004G	400 V	230 V AC mains, general-purpose rectification	Must safely block the ~325 V peak of 230 V AC
1N4005G	600 V	Mains with higher surge margin, universal-input front ends	Extra margin against mains transients
1N4006G	800 V	High-line industrial supplies	Higher line and surge conditions
1N4007G	1000 V	Maximum margin for mains, PFC and high-voltage rails	Maximum blocking safety; slight cost/availability premium

Electrical characteristics such as forward voltage, reverse leakage, and recovery time are essentially the same across the series, so thermal and dynamic behavior are comparable. The main trade-off is voltage rating versus cost and availability. In many designs, using 1N4002G instead of a higher-voltage diode can reduce margin overhead and simplify inventory, provided the peak reverse voltage never approaches the 100 V limit under normal or fault conditions.

Equivalents and cross-references: because all 1N400xG parts share the same 1 A rating, DO-41 package and pinout, higher-voltage family members are drop-in substitutes with extra margin — a 1N4004G or 1N4007G can replace a 1N4002G in most low-voltage circuits without redesign. The reverse is unsafe: never substitute a 1N4002G where a 400 V or 1000 V part is specified. This is the fastest cross-reference when a 1N4002G is out of stock.

How to Test a 1N4002G and Spot Common Failure Signs?

A multimeter in diode-test mode is all you need to check a 1N4002G in seconds. Testing the part before assembly — or when a board fails — distinguishes a bad diode from a problem elsewhere in the circuit.

Set the multimeter to diode-test mode.
Identify the anode and cathode; the cathode is marked by the band on the DO-41 body.
Forward test: place the red probe on the anode and the black probe on the cathode. A healthy silicon diode reads roughly 0.5–0.7 V (some meters show up to ~1.1 V at higher current).
Reverse test: swap the probes. A healthy diode reads OL (open / over-range) in the reverse direction.
Repeat both tests once to confirm consistent readings.

Common failure signs:

Reads near 0 V in both directions: the diode is shorted. Current bypasses the junction and downstream protection is lost.
OL in both directions: the diode is open. The circuit loses its rectification or protection path entirely.
Finite reading in reverse: the diode is leaky and may pass current in the wrong direction under load, causing overheating.
Physical damage: a cracked or charred body, discolored leads, or a burnt PCB trace around the part usually indicates a surge or sustained overload.

Test the diode out of circuit when possible; in-circuit readings can be skewed by parallel components. If the part tests healthy but the board still fails, check the soldering and the surrounding drive circuit before replacing the diode.

Good-Ark Electronics Expert Views

“The 1N400xG series remains a cornerstone of low-power discrete rectification across SMPS, automotive, and industrial applications. At Good-Ark Electronics, we focus on delivering glass-passivated and molded variants with consistent performance, tight parameter control, and robust reliability under thermal and environmental stress. For designers transitioning from legacy 1N4002G sources, our portfolio offers direct pin-compatible alternatives with matched electrical specs, supporting seamless substitution in power supplies, protection circuits, and freewheeling configurations without redesign.”

This perspective reflects Good-Ark Electronics’ position as one of China’s major rectifier and discrete-device manufacturers, with a complete supply chain from wafer development to packaging, testing, and sales, and a global technical support network.

Conclusion

The 1N4002G is a reliable, general-purpose 1 A, 100 V rectifier diode well suited for low-power AC-to-DC conversion, auxiliary SMPS circuits, freewheeling paths, and protection functions in automotive, home appliance, and industrial power equipment. Its glass-passivated DO-41 package offers strong environmental stability and simple integration, while its electrical characteristics align with the broader 1N400xG family, allowing flexible voltage scaling without changing current rating or package.

Designers should select the 1N4002G when the peak reverse voltage stays comfortably below 100 V and the application does not require high-frequency switching. For higher voltage or specialized performance, corresponding 1N400xG variants or modern fast/Schottky alternatives may be more appropriate.

For datasheets, cross-reference support, or sample requests, see the Good-Ark sample and quote guide.

FAQs

Can the 1N4002G be used for mains rectification? No. For 230 V AC mains, the peak voltage exceeds 100 V, so diodes like 1N4004G–1N4007G (400–1000 V) are required. The 1N4002G is suitable only for low-voltage applications where the peak reverse voltage remains below 100 V.
Is the 1N4002G suitable for high-frequency switching? No. Its approximately 2 µs reverse recovery time makes it unsuitable for high-frequency switching converters. It is best used at 50/60 Hz or low-frequency SMPS auxiliary circuits where slower recovery is acceptable.
What is the maximum continuous current for the 1N4002G? The 1N4002G is rated for 1 A average forward current under proper thermal conditions. Exceeding this continuously can cause overheating and failure; surge currents up to 30 A are allowed only for short pulses.
Can I replace a 1N4004G with a 1N4002G? No. Replacing a higher-voltage diode (e.g., 1N4004G, 400 V) with a 1N4002G (100 V) reduces voltage margin and risks failure if the circuit experiences voltages above 100 V.
What is the difference between the 1N4002G and the 1N4007G? They share the same 1 A current rating, DO-41 package and similar forward voltage. The only meaningful difference is reverse voltage: 100 V for the 1N4002G versus 1000 V for the 1N4007G. A 1N4007G can replace a 1N4002G in low-voltage circuits with extra margin, but the 1N4002G must never be used where 1000 V blocking is required.
What are common 1N4002G equivalents or replacements? Any 1N4002 or 1N4002G from a major manufacturer (for example Good-Ark, Onsemi, Vishay, or Diodes Inc.) is a direct equivalent in the DO-41 package. Higher-voltage family members such as the 1N4004G or 1N4007G also drop in with extra margin; verify the exact reverse voltage and thermal requirements before substituting.
Does Good-Ark Electronics offer 1N4002G-equivalent products? Yes. Good-Ark Electronics manufactures a wide range of rectifier diodes, including 1N400xG series devices with similar specifications, providing reliable alternatives for designers seeking cost-effective, high-quality discrete power components.