What is the ratio of latching current to holding current in a thyristor?

Latching Current and Holding Current Ratio Generally, latching currents are higher than the holding currents used for high rating thyristors. But they can drop to 0.4 based on the temperature as well as the driving load. Usually, the 20A thyristor used in this is BT152 and the ratio of this is 1.67.

What is the ratio of latching current to holding current?

Usually, latching currents are double or triple of holding currents for higher rating thyristors. They may fall as low as 0.4. But is usually dependent on temperature and driving load. One 20A (500V) thyristor used commonly is BT152 and it has the ratio 1.67.

What is meant by latching current & holding current?

Latching Current: It is the minimum anode current required to maintain the thyristor in the ON state immediately after a thyristor has been turned on and the gate signal has been removed. Holding Current: It is the minimum anode current to maintain the thyristor in the on-state.

What is holding current in power electronics?

The holding current (hypostatic) for electrical, electromagnetic, and electronic devices is the minimum current which must pass through a circuit in order for it to remain in the ‘ON’ state. The term can be applied to a single switch or to an entire device.

What is the importance of holding current in the thyristor?

To keep an electromechanical relay turned on, it is necessary to have a minimum current circulating in its coil. If the current falls too low the relay would turn off. The same phenomenon can be observed in a TRIAC. This minimum current which keeps the TRIAC conducting is called the hypostatic or holding current, IH.

What is the latching current of a 20 amp thyristor?

Latching Current and Holding Current Ratio Generally, latching currents are higher than the holding currents used for high rating thyristors. But they can drop to 0.4 based on the temperature as well as the driving load. Usually, the 20A thyristor used in this is BT152 and the ratio of this is 1.67.

Now coming to your question,the ratio of latching to holding current does not largely depend on thyristor current and its value varies in range 2–3. For numericals solving purpose you may consider it to be 2.5. Note: Thyristor current aka anode current.

What is the latching current of a bt152 thyristor?

Usually, latching currents are double or triple of holding currents for higher rating thyristors. They may fall as low as 0.4. But is usually dependent on temperature and driving load. One 20A (500V) thyristor used commonly is BT152 and it has the ratio 1.67.

What is the worth of holding current in a thyristor?

The worth of holding current as well as latching current is stable. So it does not be dependent on the magnitude of gate current. Holding current in thyristor or SCR can be defined as, the smallest amount of current under which anode current has to drop to enter OFF status.