What Are the Characteristics of an Ideal Silicon Diode?

Silicon diodes are among the most popular diodes in the market. They tend to enjoy a wide range of applications. In this guide, we are going to define the characteristics of an ideal silicon diode.

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What do you mean by ideal silicon diode?

The term ideal diode is used to describe a diode that acts as a perfect insulator until it is forward biased when it acts like a perfect conductor allowing current to flow without any voltage drop across it.

Even though no real diode acts exactly like an ideal diode, this term can be used to describe what happens in the junction between two semiconductors when you forward bias them by applying a suitable voltage

Let’s start with the basics of ideal silicon diode characteristics.

Forward voltage

The most important characteristic of a diode is its forward voltage drop, which is also called forward break-over voltage or just break-over voltage. It describes how much voltage a diode can handle before it will start conducting current in the opposite direction (theoretically 0 volts).

Typical forward voltage ratings are around 0.6V to 0.7V for silicon diodes.

Turning point voltage

The turning point voltage is the voltage at which a diode switches completely from the forward to reverse direction. It can be as high as 1 volt for silicon diodes, but it is also a highly variable parameter depending on the semiconductor’s make and model. The value of this parameter can be found in the manufacturer’s datasheets.

The turning point voltage is an important characteristic when you are using diodes to rectify AC signals or to protect sensitive electronic components against reverse voltages, otherwise, it is not so critical if you are using a diode in a simple circuit like an LED driver or a transistor amplifier.

Breakdown voltage (BV)

The breakdown voltage is the maximum voltage a diode can withstand before it breaks down, that is before the junction between two semiconductors becomes forward biased and starts conducting.

Breakdown voltage is not as critical as other parameters like forward voltage or turning point voltage, but it can be an important factor in circuits with high voltages and/or high currents.

The breakdown voltage of a diode depends on the semiconductor material used. Typical values range from around 1 to 2 volts for most silicon diodes, but some types can have breakdown voltages as high as 6 volts.

How do we specify the forward voltage of a diode?

The forward voltage of a diode is specified as the difference in voltage between the cathode and anode terminals when the diode is conductive.

This means that if you measure the voltage across an ideal silicon diode with your multimeter when it is forward biased, it will read 0 volts.

The forward voltage of a diode is not the same as the voltage drop across a diode when it is conducting current.

How do you measure the forward voltage of a silicon ideal diode?

The forward voltage of a diode can be measured using your multimeter by applying a suitable forward bias across the diode and measuring the voltage between its terminals. The multimeter should have an appropriate range for this measurement.

If you are using an analog multimeter to measure the forward voltage, it is important that you ensure that its leads do not inadvertently act as antennas and couple high-frequency signals from its power supply into your circuit. This could seriously affect your reading and affect your measurements.

If your multimeter is a digital multimeter you should also ensure that its measurement circuitry is not affected by the high-frequency signals.

What devices are ideal diodes used in?

Diodes are used in many electronic circuits, devices, and equipment. Examples include:

– Rectifiers in power supplies to convert alternating current (AC) to direct current (DC)

– In many types of light dimmer circuits

– In solar panels to prevent reverse current flow when the voltage is negative

– As a one-way valve in the heart pacemaker circuit to ensure that all pulses are generated by the pacemaker and not by the heart

– High-frequency switching circuits

– Oscillator circuits. In this application, diodes are often used together with capacitors and inductors to form simple oscillators or as part of a phase-locked loop. The diodes provide isolation from the supply rail so that only a small amount of energy is required to maintain oscillation.

Difference between Ideal silicone diode vs real diode

The diode is a two-terminal device that allows current to flow in one direction only. The diode is a semiconductor device and has three terminals: anode, cathode, and gate. The diode is also known as a rectifier, one-way valve, non-linear resistor, or silicon controlled rectifier (SCR).

The ideal diode has infinite resistance in the reverse direction and zeroes resistance in the forward direction. It has zero voltage drop during forwarding conduction and infinite voltage drop during reverse conduction.

The real diode has finite conductance in both forward and reverse directions. Thus it has a finite voltage drop across it during forwarding conduction and finite current through it during reverse conduction.

The ideal diode has zero voltage drop during forwarding conduction and infinite voltage drop during reverse conduction. The real diode has finite conductance in both forward and reverse directions. Thus it has a finite voltage drop across it during forward conduction and finite current through it during reverse conduction.

The ideal diode is a short circuit in the reverse direction and an open circuit in the forward direction. The real diode is a very high impedance in the reverse direction and a low impedance in the forward direction.

The ideal diode is a lossless device that passes current without any power loss, but real diodes have losses due to internal resistance, contact resistance, and junction leakage current which are temperature-dependent.

How to buy an ideal silicon diode?

There are various things to look at when buying an ideal silicon diode.

Voltage rating

The diode has to be rated for the voltage of the circuit. For example, if the circuit is rated at 25V then the diode has to be rated for 25V or more.

Current rating

The maximum current that can flow through it should not exceed its rating. If more current flows through it than its rating, it will get damaged or destroyed. The maximum current that can flow through it should not exceed its rating.

Impedance

The diode has to have the right impedance for the circuit. If the impedance is not right, then the circuit will not work properly or even some of its parts may get damaged.

Forward voltage drop

The voltage drop across it during forward conduction should not be more than its rating. If it is more than its rating, then it will get damaged or destroyed.

Reverse breakdown voltage

The diode should not conduct in the reverse direction when the voltage across it exceeds some value called the breakdown voltage.

Cost

The cost of a diode depends on the type of diode and its rating.

Reverse leakage current:

The diode should not conduct when the voltage across it is very low. The diode conducts even when the voltage across it is very low and thus it wastes power.

Conclusion

I hope you have learned something valuable about ideal silicone diodes. The topic of ideal diodes is very important in electronics. It will help you understand the real diode better.

Do not forget to consult ICRFQ whenever you want to buy ideal silicon diodes in China.

ICRFQ is one of the most professional ideal silicone diodes suppliers in China. If you want to buy high-quality ideal diodes, please feel free to contact us.