Why diode is called active device

A resistor does NOT store charge, it merely lessens the current flow. You said devices which produce energy are called active components, on the other hand, you said active components are energy aceptors?

Did you get it…. The capacitor stores charge initially and then it starts conducting, why is it not an active component then, like the diode which does not start conducting till it gets 0. You have specified it in very easy way. No you are going to have to rerun all new service. Its not hard. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email.

Active Components: Those devices or components which required external source to their operation is called Active Components. So it is required an External Source to its operation.

Because, If we connect a Diode in a Circuit and then connect this circuit to the Supply voltage. I think you got it :. Those devices or components which do not required external source to their operation is called Passive Components. Thread starter chinusneha Start date Jan 8, Status Not open for further replies. Diode is active or passive and why??? Last edited: Jan 8, Miles Prower Member. A diode is definitely a passive device.

It takes no power from a DC rail to convert the DC into another type of signal. Consider a crystal set: it requires no battery or other external source of power other than the RF it's demodulating. Sceadwian Banned. Diodes are capable of acting as switches, in other words they are capable of controlling the electricity which is flowing through them, they even have linear regions which can be used for amplification though not nearly as good as a transistor, this makes them active devices.

Everywhere I've looked there is only one definition for something to be called an active device, and that is. An active device is any type of circuit component with the ability to electrically control electron flow.

Click to expand Last edited: Jan 9, Hello there, I assume we are talking about a regular diode, and not a special diode type like a tunnel diode. I was taught that in order to qualify as an active device, the device has to be capable of delivering an infinite amount of energy. That means voltage and current sources pretty much, and probably anything that can be made from voltage and current sources.

A diode on the other hand, is a consumer of energy and therefore can not be an active device. Many people share this view also. For example, 5. Passive elements can only approximate this behavior. My personal view is that anything or it's model that can supply energy is active, and anything that consumes energy is passive. This isnt percent accurate but it seems more like what most people i've talked to over the years think.

In other words, a power supply is active because it can deliver energy. Another thing to think about is: Is a light dependent resistor LDR an active element? See if you can answer this one too. Last edited: Jan 11, Vizier87 Active Member. I'll give it a shot Since it covers photoelectric effect? Waiting with eyes wide open. MrAl, I'm sorry but that has no basis in any information I've ever found, I have found no definition anywhere that requires an active device to use power, the ONLY requirement I am aware of to be called an active device is that the device must be capable of controlling the electron flow through it, which the diode qualifies for because it's two gate voltages determine weather or not it can conduct current, hence active.

Passive devices aren't capable of controlling current through themselves. All semiconductors are active devices. LDR's are active devices, more obviously than a diode is. The main reason some sites reference a diode as being a passive device is because there's no way to separately control it's switching function, IE it has no gate.

This does not however preclude it from being an active device as it controls electron flow, based on applied voltage. Active Device: Active devices are those semiconductor devices which need some voltage to start their operation. For example, diode transistors. Passive Device: Passive devices are those semiconductor devices which does not need any voltage to start their operation.

For example, resistor, inductor, and capacitor. Why Diode is called Active Device? The diode is an active device because to start its operation we need to give some voltage across it. The small voltage to start the operation of the diode is called the Threshold Voltage. We know that the threshold voltage of a silicon diode is 0. The threshold voltage of a germanium diode is 0. Why Transistor is called Active Device? Transistor also needs some voltage to start its operation that's why it is called Active Device.

To properly operate a transistor we need to give proper biasing.