How can I make a simple radio at home?
You can make your own simple AM radio antenna using a piece of wire. Use a small diameter insulated wire, such as a 20 or 22-gauge, and cut it to a length of at least 15 or 20 feet (4.6 or 6.1 m). To boost the reception, coil the wire in a circle and use zip ties or electrical tape to keep the coil from unraveling.
What is a germanium diode?
Germanium diodes are made from germanium. They used to be used a lot in early electronics, such as radios, but they have largely been replaced by silicon diodes. Even though silicon diodes are more popular today, germanium diodes still offer some advantages that silicon diodes don’t.
How can you tell if a diode is germanium?
Measuring Forward Bias Voltage Set your DVM/DMM to the diode test mode , it should provide you with the respective voltage drop. If the figure is 0.3 V or less, the diode is a germanium type. If the voltage drop is 0.7 V or less the diode is a silicon diode.
Which is better silicon or germanium?
The structure of Germanium crystals will be destroyed at higher temperature. However, Silicon crystals are not easily damaged by excess heat. Peak Inverse Voltage ratings of Silicon diodes are greater than Germanium diodes. Si is less expensive due to the greater abundance of element.
What is difference between silicon and germanium?
Each has four valence electrons, but germanium will at a given temperature have more free electrons and a higher conductivity. Silicon is by far the more widely used semiconductor for electronics, partly because it can be used at much higher temperatures than germanium.
Why leakage current is more for germanium diode?
Much of the leakage current is due to surface conduction, related to the lack of cleanliness of the semiconductor surface. Both leakage currents increase with increasing temperature, approaching a µA for small silicon diodes. For germanium, the leakage current is orders of magnitude higher.
Why silicon is used in Zener diode?
Silicon does not get damaged easily due to excess heat. Variation of Ic0 with temperature is not much hence thermal stability is maintained. Also reverse voltage of silicon diode is higher. Therefore silicon is the most used material for manufacturing diodes.
Why germanium is not used in SCR?
Ability to withstand at high temperature: silicon crystals have capability to withstand at higher temperature compare to germanium crystals . So if leakage current is produced in SCR it heats up the device then silicon crystals can withstand but not germanium crystals.
What is silicon diode?
A silicon diode is a semiconductor that has positive and negative polarity, and can allow electrical current to flow in one direction while restricting it in another. The element silicon, in its pure form, acts as an electrical insulator. This means that 0.7 volts is needed to power the diode.
How does zener diode works?
The Zener diode operates just like the normal diode when in the forward-bias mode, and has a turn-on voltage of between 0.3 and 0.7 V. As the reverse voltage increases to the predetermined breakdown voltage (Vz), a current starts flowing through the diode.
What is the most common diode?
The most commonly used signal diode is the 1N4148. This diode has a close brother called 1N914 that can be used in its place if you can’t find a 1N4148. This diode has a forward-voltage drop of 0.7 and a peak inverse voltage of 100 V, and can carry a maximum of 200 mA of current.
What is the meaning of Zener diode?
A Zener diode is a silicon semiconductor device that permits current to flow in either a forward or reverse direction. The diode consists of a special, heavily doped p-n junction, designed to conduct in the reverse direction when a certain specified voltage is reached.
What is meant by zener voltage?
The Zener voltage is the voltage at which the depletion region completely vanish. The reverse bias applies across the diode increases the intensity of electric field across the depletion region. Thus, it allows the electrons to move from the valence band of P-type material to the conduction band of N-type material.
What is Zener effect and Avalanche effect?
The Zener and the avalanche effect may occur simultaneously or independently of one another. In general, diode junction breakdowns occurring below 5 volts are caused by the Zener effect, whereas breakdowns occurring above 5 volts are caused by the avalanche effect.
What if Zener diode is forward biased?
When Zener diode is biased in the forward direction it behaves like a normal signal diode passing the current increasing linearly with voltage, but as soon as a reverse voltage applied across the Zener diode attains the breakdown voltage of the device, a large current starts to flow through the diode.
What’s the difference between a diode and a Zener diode?
A diode is a semiconductor device which conducts in one direction only. A Zener diode is a semiconductor device which conducts in forward biased as well as reversed biased. A normal diode if operated in reversed biased will get destroyed.
What is the current through the Zener diode?
As we see that the resistance R2 and Zener diodes are connected in parallel so the voltage across them is equal, so the potential difference across R2 is also 10 Volts. Potential difference across R2=10. Let, Potential difference acrossR1beV1. Therefore, current through Zener diodes would be 3.3mA.
Why is there a sudden increase in current in zener diode?
When Zener diode is connected in reverse bias, as applied voltage reaches at Zener breakdown voltage, due to rupture of bonds there is a sudden increase in current in Zener diode.
Does Zener diode obey Ohm’s law?
Diodes do not follow Ohm’s Law. But. At any given current level, you can measure the change in voltage (ΔV) for small changes in current (Δi), and get a local equivalent resistance called dynamic resistance.
How do you identify a zener diode?
The testing of Zener diodes is the same as the regular diodes. The multimeter is placed in the diode setting and connected to the diode. The forward biased voltage of the diode is found by connecting the positive of the multimeter to the diode’s anode. This is the side on the Zener diode that is not marked.
What happens when zener diode is connected in series?
In this case, one Zener diode will be forward biased while the other is reverse biased. In the end-to-end arrangement, the cathode of one diode is connected to the anode of another diode, so both will be forward biased or both will be reverse biased. End-to-end and back-to-back current-voltage diodes in series.
How do you identify a 12v zener diode?
Note place a diode across the meter probes. One way they’ll read a low voltage (under 1V). The other way, if they read less than 18V then the diode is likely to be a zener diode. The voltage you see on the multimeter is the zener diode voltage.
Is 1N4148 a zener diode?
1N4728A Zener Diode 1W 5%….Details, datasheet, quote on part number: 1N4148.
| Part | 1N4148 |
|---|---|
| Category | Discrete => Diodes & Rectifiers => General Purpose Diodes |
| Title | Small Signal |
| Description | 1N4148 Signal Diode. Breakdown Voltage BV = 75V(IR = 5.0uA), BV = 100V(IR = 100uA) |
| Company | Rectron |
Can I use 1N4007 instead of 1N4148?
The 1N4007 is physically bigger and designed for higher current and voltage loads than the 1N4148, but in this case it should be a suitable replacement. Though both are just normal diodes, they are meant for totally different purposes. You should check the datasheet of both. Maximum Forward current.
Can I use 1N4007 instead of 1N4001?
Yes. The 1N4007 can withstand a higher reverse voltage(Vr), 1000V vs. (The 1N4001 is rated for a Vr(RMS) of 35V.) While diodes like 1N400x may be well suited as freewheeling diodes in terms of voltage and current (rated at 1A), they’re not exactly fast.
How do you use zener?
A zener diode is always operated in its reverse biased condition. As such a simple voltage regulator circuit can be designed using a zener diode to maintain a constant DC output voltage across the load in spite of variations in the input voltage or changes in the load current.