Often on the shelves of stores selling radio components, you can find flashing LEDs. They are different in strength and color of the glow. Flashing LEDs (MBD) are semiconductor elements with built-in integrated pulse generators, the flash frequency of which is 1.5-3Hz.
Many radio amateurs believe that these devices are useless and it is better to replace them with cheaper indicator LEDs. Perhaps they are right about something. However, MSD also have the right to exist. Let's try to figure out what are the advantages of such products.
Flashing LEDs, in fact, are complete functional devices, the main purpose of which is to attract attention, that is, the function of light signaling. It is also worth noting that flashing semiconductor elements do not differ in size from standard indicator LEDs. However, despite its compact size, the MSD includes semiconductor chip generators, as well as some additional elements. If designpulse generator on conventional radio components, then this design would have a fairly solid size. It's worth noting that flashing LEDs are pretty versatile. The supply voltage of such elements lies in the range of 1.8-5 V for low-voltage devices and 3-14 V for high-voltage ones. The photo below shows a flashing 12 volt LED.
Advantages of MSD:
- wide range of supply voltage (up to 14 volts);
- small overall dimensions;
- fairly compact light signaling device;
- different colors of radiation. Some blinking LED options have several built-in color diodes with different flashing intervals (the photo shows a blinking yellow LED);
- the use of MSD is justified in small devices that have strict requirements for the size of the element base and power consumption. These diodes, due to their electronic circuit, assembled on MOS structures, have a low current consumption with a sufficiently high glow power;
- a flashing semiconductor device can even replace a functional unit.
On the circuit diagrams, the graphical representation of the MSD differs from the conventional LED only by the dotted lines of the arrows, which symbolizes the flashing properties of the element.
Let's take a closer look at the design of flashing LEDs. Through the transparent case of the element, you can see that structurally the diode consists of two parts. The light emitting crystal is located on the base of the cathode (negative) electrode, and the chip generator is located on the base of the anode (positive electrode). All parts of this device are connected by three gold jumpers. The chip oscillator is a high-frequency master oscillator that runs constantly, its frequency fluctuates around 100 kHz. Also on the blinking diode circuit there is a divider assembled on logical elements. It divides the high frequency value to the level of 1.5-3Hz. You may ask: "What is a high-frequency oscillator with a divider used for, why couldn't a low-frequency oscillator be used, and thereby simplify the design?" This is due to the fact that the implementation of a low frequency generator requires a large capacitor for the timing circuit. To implement such a capacitor, a much larger area would be required than for the use of a high-frequency generator.
So we looked at what a blinking LED is. And to the question of which is better - MSD technology or traditional indicator diodes, we will answer that despite the cheapness of the latter, flashing diodes have also found their scope and do not compete with traditional ones.
