Kingtronics Blog

Rectifier diodes (large current)

Rectifier diodes are used in power supplies to convert alternating current (AC) to direct current (DC), a process called rectification. They are also used elsewhere in circuits where a large current must pass through the diode.

All rectifier diodes are made from silicon and therefore have a forward voltage drop of 0.7V. The table shows maximum current and maximum reverse voltage for some popular rectifier diodes. The 1N4001 is suitable for most low voltage circuits with a current of less than 1A.

As you know, general diode rectifier M7, 1N4007 and switching diode LL4148 are very common and popular in the market. This year, we win really good diode orders.

To support customers better, Kingtronics prepare stocks on offer. So the price and lead time are very attractive.

Pls note all the parts are NEW and Original. First come, first served. We will replenish stock once use out. Do you have any order plan now?

Stock status:

Axial Diode 1N4007 DO-41 T&R RoHS. 1,500,000pcs in stock (US$ 0.0057/pc)

SMD Diode M7 DO-214AC T&R RoHS. 550, 000pcs in stock

Switching Diode LL4148 LL-34 T&R RoHS. 2,000,000pcs in stock

Pls visit our website www.kingtronics.com for details.

In 1938, German scientist Walter Schottky developed a diode having a metal to semiconductor junction.

A Schottky diode, like other solid-state diodes, conducts electrical current in one direction.

It can operate at higher speeds than typical silicon diodes.

Advantages

Small pockets of electric charge build up in a typical silicon diode, slowing down its ability to turn current off.

A Schottky diode can operate hundreds of times faster since it avoids build up of electric charges.

It also has less than half the voltage drop conducting in the forward direction than a silicon diode.

Applications

Engineers use Schottky diodes in very high-frequency circuits, such as microwave transmitters.

Schottky diodes also see use in switching power supplies and solar battery charging systems.

Kingtronics produce and sell schottky diode 1N5817-1N5819, 1N5820-1N5822. if you have inquiry, pls send email to anna@kingtronics.cn.

Silicon diodes act as one-way valves for electrical current, allowing it to flow in only one direction. Like any electronic component,

diodes can fail from excessive voltage or current. Fortunately, diodes are simple to test, needing only a good multimeter to check them.

If you set the multimeter to read resistance and put the probes across the diode, you should read a low resistance one way and high resistance

with the probes reversed. A shorted diode will read low resistance both ways, and a blown diode will read high resistance both ways.

Instructions

1.Turn off the power to your circuit or equipment. Let the equipment sit for at least 30 minutes before removing the case or cover to allow the power supply to discharge。

2.Locate the diodes you want to test. They are typically small, two-lead parts with a stripe on the body to indicate the diode's cathode side.

3.Turn the multimeter on and turn the function knob so it points to the resistance setting. Hold the plastic body of the probes and are not touching the metal tips.

Touch the tip of the positive probe to one side of the diode and the negative probe to the other side. Read the resistance measurement and write it down.

Reverse the probes so they're touching the opposite sides of the diode. Write down the resistance you read . The higher resistance should be at least 10

times greater than the lower one. If it's less than five, the diode is very likely bad.

Kingtronics produce many types of diode rectifier,such as silicon diode, switching diodes, fast recovery diodes zener diodes.... Pls visit our updated website www.kingtronics.com for the details.

Any inquiry, pls send to anna@kingtronics.cn . Many thanks!

There are a number of different electronic devices which tend to be called diodes.

Although they're made differently they all have three things in common.

They have two leads like a resistor.
The current they pass depends upon the voltage between the leads.
They do not obey Ohm's law!

As an example we will use a typical diode called a pn-junction. This allows us to explain behaviour of diodes.

The function of a diode is to allow current in one direction and to block current in the opposite direction.

The terminals of a diode are called the anode and cathode. There are two kinds of semiconductor diodes: a P-N junction diode, which forms an electrical barrier at the interface between N- and P-type semiconductor layers, and a Schottky diode, whose barrier is formed between metal and semiconductor regions.

Remember, however, that there are other sorts of diodes which are built differently but show the same general behaviour.

Rectifiers find a use in detection of amplitude modulated radio signals. The signal may be amplified before detection, but if un-amplified, a very low voltage drop diode must be used. When using a rectifier for demodulation the capacitor and load resistance must be carefully matched. Too low a capacitance will result in the high frequency carrier passing to the output and too high will result in the capacitor just charging and staying charged.

Kingtronics’s fast recovery rectifier diodes are very popular in the overseas market, According to the rectifier’ s application , Our Kingtronics managing ordinary rectifier diodes, ultra-fast rectifier diodes. In our Kingtronics website www.kingtronics.com ,we have detailed PDF about all kinds of diodes & rectifiers.

Since the voltage dropped across a Zener Diode is a known and fixed value, Zener diodes are typically used to regulate the voltage in electric circuits. Using a resistor to ensure that the current passing through the Zener diode is at least 5mA (0.005 Amps), the circuit designer knows that the voltage drop across the diode is exactly equal to the Zener voltage of the diode.

NEW Click here to visit Zener-Diode.co.uk for a site dedicated to zener diodes, their characteristics, usage, and other information.

Zener Diode Voltage Regulator Circuit

A zener diode can be used to make a simple voltage regulation circuit as pictured above. The output voltage is fixed at the zener voltage of the zener diode used and so can be used to power devices requiring a fixed voltage. Click here to find out more about the Zener Diode Voltage Regulator and how you go about selecting the resistor and zener diode.
NEW The above mentioned article on zener diode voltage regulators has now been updated and a handy calculator has been added to help you select the correct resistor and zener diode values and power ratings.

Zener Diodes in Series With Loads

If you have a regulated fixed voltage - say 12 Volts from a desktop PC power supply, and you want to power something requiring a lower voltage, it is possible to simply place a zener diode in series with the load device. You would choose a diode with a zener voltage equal to the supply voltage minus the voltage drop across the load.

For example, if you have a 1 Watt 6 Volt lightbulb to power from a 12 Watt regulated power supply, a 6.2V zener diode could be placed in series with the bulb giving the bulb 5.8V, or you could overpower the bulb a little using a 5.6V zener diode and dropping 6.4V across the bulb. Heat would be generated in the zener diode so it is essential to calculate the power lost in it so a suitably rated diode could be chosen.

Using a 5.6V zener diode, and knowing the bulb draws a current of around one-sixth of an Amp, we can calculate the power loss in the diode (with Ohm's Law) to be just under 1 Watt. Therefore a standard 1.3 Watt zener diode should be up to the job.

Circuits with Zener Diodes

Zener diodes are key components in the circuits presented in the following articles: Make a Simple Battery Status Monitor, LM741 Voltage Indicator, and High Capacity Alternative to 9V Battery.

Zener diodes are used to maintain a fixed voltage. They are designed to 'breakdown' in a reliable and non-destructive way so that they can be used in reverse to maintain a fixed voltage across their terminals.

Zener diodes can be distinguished from ordinary diodes by their code and breakdown voltage which are printed on them. Zener diode codes begin BZX... or BZY... Their breakdown voltage is printed with V in place of a decimal point, so 4V7 means 4.7V for example.

Kingtronics supplies BZV55C/ZMM55C-SERIES with Low zener impedance,Low regulation factor,Glass passivated junction,High temperature soldering guaranteed:260 C/10S at terminals. Please link http://www.kingtronics.com/pdf/BZV55C.pdf ,you will see all series of our Zener diodes.

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction) while blocking current in the opposite direction (the reverse direction). Thus, the diode can be thought of as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, and to extract modulation from radio signals in radio receivers.

Different types of diode will have different function, this is depends on their voltage, temperature, and other factor. So it is very important when you check your diode, Our Kingtronics provide diode's detailed function. If you have any problems, please look for some suggestions in www.kingtronics.com.

A Zener Diode is a special kind of diode which permits current to flow in the forward direction as normal, but will also allow it to flow in the reverse direction when the voltage is above a certain value - the breakdown voltage known as the Zener voltage.

The Zener voltage of a standard diode is high, but if a reverse current above that value is allowed to pass through it, the diode is permanently damaged. Zener diodes are designed so that their zener voltage is much lower - for example just 2.4 Volts. When a reverse current above the Zener voltage passes through a Zener diode, there is a controlled breakdown which does not damage the diode. The voltage drop across the Zener diode is equal to the Zener voltage of that diode no matter how high the reverse bias voltage is above the Zener voltage.

The illustration above shows this phenomenon in a Current vs. Voltage graph. With a zener diode connected in the forward direction, it behaves exactly the same as a standard diode - i.e. a small voltage drop of 0.3 to 0.7V with current flowing through pretty much unrestricted. In the reverse direction however there is a very small leakage current between 0V and the Zener voltage - i.e. just a tiny amount of current is able to flow. Then, when the voltage reaches the breakdown voltage (Vz), suddenly current can flow freely through it.