Comprehensive Guide to 1N4007: Specifications and Typical Applications

2025-08-18 16:57

In the world of electronic components, diodes play a fundamental yet critical role—they are found on virtually every circuit board. Among them, the 1N4007 stands out as a classic rectifier diode, widely adopted due to its high reliability, low cost, and high current capability. This article provides a detailed overview of the key specifications of the 1N4007 (such as reverse voltage, forward current, and recovery time), analyzes its typical application circuits (e.g., bridge rectification and flyback protection), and offers a selection guide comparing it with other models in the 1N400x series.

1. Specification Breakdown

1.1 Electrical Characteristics (Typical @ 25°C)

Parameter	Symbol	Typical Value	Test Conditions	Notes
Forward Voltage Drop	VF	1.1 V	IF = 1 A	Increases slightly with current
Reverse Leakage Current	IR	5 μA	VR = 1000 V	Increases at high temperature
Junction Capacitance	CJ	15 pF	VR = 4 V, f = 1 MHz	Affects high-frequency performance
Thermal Resistance	RθJA	50 °C/W	Without heatsink	Impacts thermal design

1.2 Absolute Maximum Ratings

Parameter	Symbol	Maximum Value	Description
Peak Repetitive Reverse Voltage	VRRM	1000 V	Breakdown may occur if exceeded
Average Forward Current	IO	1 A	Long-term continuous operation limit
Peak Forward Surge Current	IFSM	30 A	8.3 ms single half sine wave pulse
Operating Junction Temperature	TJ	-65°C to +175°C	Beyond range may cause device failure

1.3 Switching Characteristics

Parameter	Symbol	Typical Value	Description
Reverse Recovery Time	trr	30 μs	Affects high-frequency performance
Reverse Recovery Charge	Qrr	5 μC	Major contributor to switching loss

2. Typical Applications

From the analysis of its core parameters, we can clearly see the limitations and strengths of the 1N4007:

1000V reverse voltage makes it ideal for line-frequency rectification
1A continuous current suits most low-power applications
30 μs recovery time defines its upper frequency limit

2.1 AC Mains Rectification (Core Application)

Use Cases:

Household appliances (e.g., fans, chargers, small adapters)
Secondary-side rectification of transformers in industrial control systems

Example: Emergency Fan Power Supply Circuit

The circuit features a bridge rectifier (comprising four 1N4007 diodes), a voltage regulator, and a relay-driven fan switch. The four diodes convert AC to DC, while D1 protects against inductive voltage spikes across the relay coil, and D2 prevents reverse current flow.

Parameter Fit:

1000V reverse voltage handles 220V AC input (after transformer step-down, peak voltage is <700V), providing safe margin
1A average forward current supports devices in the 5W–20W range such as mobile chargers or LED drivers

Typical Topologies:

Full-bridge rectification (4 × 1N4007)
Half-wave rectification (1 × 1N4007)

In a full-bridge circuit, the four diodes alternate conduction in each AC half-cycle to deliver a smooth DC output, ensuring stable performance.

2.2 Low-Power DC Protection

Use Cases:

As reverse polarity protection diode (series with DC input)
As a flyback diode across relays/motors to absorb inductive spikes

Parameter Fit:

1A current rating can handle relay or small DC motor pulses
High voltage tolerance helps absorb inductive back-EMF (a 12V relay may generate >100V spikes)

2.3 Low-Frequency Pulse Circuits

Use Cases:

Low-frequency PWM dimming (e.g., post-TRIAC dimmer for lamps)
Low-speed signal detection (e.g., audio peak detection where speed isn't critical)

Limitations:

30 μs reverse recovery time restricts operation to frequencies below 1 kHz
(Acceptable at 1 kHz; losses increase dramatically above 10 kHz)

3. Selection Guide

In circuit design, the choice of rectifier diode directly affects efficiency, reliability, and cost. As a classic line-frequency rectifier, the 1N4007 is widely used in AC-DC converters, reverse polarity protection, and flyback circuits.

Comparison with 1N400x Series

Model	Max Reverse Voltage	Avg Rectified Current	Surge Current	Typical Applications
1N4001	50 V	1 A	30 A	Low-voltage circuits (5V–12V)
1N4002	100 V	1 A	30 A	12V–24V power supplies
1N4003	200 V	1 A	30 A	24V–48V industrial systems
1N4004	400 V	1 A	30 A	Medium-voltage AC (e.g., home appliances)
1N4007	1000 V	1 A	30 A	High-voltage rectification (e.g. 220V AC)