Common methods of reverse-voltage protection employ diodes to prevent damage to a circuit. In this article alternative methods of using relays are discussed. This way achieve zero voltage drop on the circuit and effectively protect the system.
Simple reverse-polarity-protection circuit has no voltage drop - [Link]
After the recently introduced 1A diode SKL14, we introduce you the 3A type in the same miniature PowerSOD-123T package.
New Schottky diode SKL34 features almost the same possibilities of usage like SKL14, which was recently introduced in our article: SKL14 – 1A Schottky diode will fit everywhere. The main difference is that SKL34 can be used even in more powerful applications with higher currents.
If SKL14 surprises by its max. current in such a small package, than it could be said, that SKL34 shocks by its 3 Amps. A very high current is enabled by a thermally enhanced PowerSOD-123T package with extended solder pads. Detailed information will provide you the SKL34 datasheet.
In case of interest, please contact us at email@example.com.
SKL34 – another surprisingly small 3A Schottky diode - [Link]
By Lee H. Goldberg:
The Schottky bypass diodes used in most cell-based solar panels serve as a protection mechanism that allows the panel to continue producing power when one of its cell strings is shaded or damaged. However, the characteristics of traditional diodes create energy losses that reduce the overall efficiency of a solar power system and, in some situations, may actually cause costly damage. To solve this problem, several manufacturers have introduced a new class of “active diodes” that use transistors to produce diode-like behavior, while allowing the solar panels they protect to operate with higher efficiency and better reliability. This article will explore the technology that underlies active diodes, look at the products currently on the market, and look at how they are changing the way solar panels are being designed and manufactured.
Active Bypass Diodes Improve Solar Panel Efficiency and Performance - [Link]
SKL14 can be used in switch-mode power supplies or as protection diodes and thanks their really miniature dimensions, they are also suitable at the lack of PCB space.
SMT Technologies enable a substantial increase of current density thanks to a very good heat transfer from a component to a PCB. Almost a zero length of „leads“ of SMT components also features another positive aspects like a significant suppression of a parasitic inductancy and a possibility to construct circuits with a high components density and a minimal PCB tracks length, what significantly decreases an undesired radiation (EMI) for example in switch-mode power supplies.
A very small forward voltage drop <0.55V/1A and the speed of Schottky diodes make the SKL14 a universal diode suitable for example for rectifying, for SMPS or as a reverse polarity protection diode. A relatively high current is mainly enabled by a Power SOD-123 package with enhanced thermal properties.
SKL14 – 1A Schottky diode will fit everywhere - [Link]
After a big response on the CL20M45 current limiting diode, we decided to add the type CL40M45 with a double nominal current. That´s why you´re free to choose from 2 types, and thus add a bigger variability to your LED applications.
In the article „Drive LEDs from 230V mains more simply and reliably“ we described to you the principle and usage of current limiting diodes (CLD) in detail. A new type in our offer – CL40M45 features a nominal current of up to 40 mA. Other specification is identical to the type CL20M45, especially Umax 45V and Ptot 1W.
By a simple replacement of CL20 for CL40 we can reach a significant change of a current flowing through LED diodes in the application. This can be convenient for example at designing a device with an adoptable power – at the production, it is possible to choose the type CL20M45 or CL40M45 – depending on customer´s requirements (higher light output or power saving at a lower light output). At the same time, this provides a possibility to reach a wide current range at parallel connection of various CLDs, without a need to modify the PCB.
As it is clear from the first sight, a higher maximum current through a CLD also means a higher heat generated on the chip itself. Both types feature max. power dissipation of 1W, that´s why it is necessary to take this fact into account at the circuit design. While at the CL20M45 it is possible to operate with the continuous current of 20mA up to a maximum operating voltage of 45V (P=0,02Ax45V=0,9W), at the CL40M45 the thermal loss (1,8W) would already be too high. That´s why the maximum continuous operating voltage on the CL40M45 is approx. 25V and the „reserve“ up to 45V is usable for elimination of spikes or disturbances in power supply and similar. For further increasing of durability and reliability, it can be useful to design a PCB with enlarged copper pads serving for trouble-free heat dissipation from the CLD.
LED diodes from the 230V mains on 2 ways - [Link]
This video covers the basics of diodes, bridge rectifiers, and how to build simple unregulated AC to DC power supplies than can handle a few mA up to several Amps. Diode Tutorial & How to build an AC to DC power supply - [Link]
Zener diode is a special diode, unlike normal diodes zener diodes are intended to work in the breakdown voltage. These components maintain constant voltage at its terminals. This is a circuit to help you find out what’s the breakdown voltage of your diodes.
- Read Vz value of zener diode in Led display
- Zener diode tester range: 1V to 50V
- Two scales 5mA and 15mA test
Zener diode tester 1V to 50V - [Link]
With this tool you can test various electronic components like diodes, LEDs, all kinds of transistors (PNP, NPN, several types of MOSFETs), capacitors, resistors as well as triacs and thyristors. It will show you several physical characteristics after the test was completed, like forward voltages, (gate) capacity and amplification factor. More over, it will show the polarity of the component and identifies the several pins of a package. A very nice and sophisticated project I host for Markus Frejek. I’ve done an additional layout for the device you can see on the left side. This project has found a lot of fans, including myself. The device is powered by an AVR ATmega 8 MCU.
Component tester - [Link]
Basics: Introduction to Zener Diodes @ Evil Mad Scientist Laboratories – [via]
Zener diodes are a special type of semiconductor diode– devices that allow current to flow in one direction only –that also allow current to flow in the opposite direction, but only when exposed to enough voltage. And while that sounds a bit esoteric, they’re actually among the handiest components ever to cross an engineer’s bench, providing great solutions to a number of common needs in circuit design.
In what follows, we’ll show you how (and when) to use a Zener, for applications including simple reference voltages, clamping signals to specific voltage ranges, and easing the load on a voltage regulator.
Basics: Introduction to Zener Diodes - [Link]
After our recent post about the commercial semi-conductor tester we started a discussion about building a similar open source project. What came up is this AVR based transistor tester (machine translation) by Markus.
It’s built around an ATmega8 IC that interfaces with a standard HD44780 16×2 character LCD. The circuit that does the testing is simplicity itself. Three pairs of resistors are connected to 6 pins of the microcontroller, and each pair is connected on the other end to one of the transistor pins.
The theory of operation is also relatively simple. The microcontroller cycles through different patterns on its output pins until a recognizable pattern is read on its input pins. It supports a very large range of devices:
- NPN and PNP bipolar junction transistors.
- P and N channel, enhanced and D type mosfet transistors.
- P and N channel JFET transistors.
- Common anode and common cathode dual diodes.
- Two diodes in connected in anti-parallel or series configuration.
- Single diode.
AVR-based transitor tester - [Link]