Table of Contents
- 1 What is meant by holding current?
- 2 What is the relation between IH and IL?
- 3 How do you calculate holding current?
- 4 How is holding current measured?
- 5 What is triggering in SCR?
- 6 Which triggering is the most reliable?
- 7 What’s the difference between a holding current and a latching current?
- 8 How is the latching current related to the gate signal?
What is meant by holding current?
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. A simple example of holding current is in a Spark gap.
What is the relation between IH and IL?
The holding current value IH (refer to AN302 for holding current) is linked to the latching current value IL. For the most TRIACs (rated current lower than 40 A), the IL value is higher than the IH value. The IL / IH ratio is related to the TRIACs current rating, as shown Table 2.
What is meant by latching current?
The latching current is defined as the minimum value of anode current which it must attain during turn on process to maintain conduction when gate signal is removed.
Which current is greater holding or latching?
Holding Current: It is the minimum anode current to maintain the thyristor in the on-state. Latching current is always greater than holding current.
How do you calculate holding current?
Once the current through the SCR i.e. anode current Ia falls below holding current, the current becomes zero. This means the SCR stops conducting….Difference between Latching and Holding Current.
| Sr. No. | Latching Current | Holding Current |
|---|---|---|
| 1) | It is related with turn on process of SCR or thyristor. | It is related to turn off process. |
How is holding current measured?
The holding current is always measured with the gate unconnected, that is disconnected from the trigger circuit and without bias. However, sensitive SCRs, that is, those with a gate trigger current IGT of 200 µA or less, are measured with a 1 kΩ resistor connected between gate and cathode.
What is holding voltage?
The term holding current may refer to: Holding voltage (physiology), in electrophysiology, specifically while voltage clamping a cell, the holding current is the current that is passed into the cell in order to hold it at the command potential.
What is the difference between latching and holding in gate triggering?
Latching current of forward biased SCR is the minimum current which anode current must attain to continue to remain in forward conduction mode even when gate current is removed….Difference between Latching and Holding Current.
| Sr. No. | Latching Current | Holding Current |
|---|---|---|
| 3) | Value of latching current is more than that of holding current. | It is less than latching current. |
What is triggering in SCR?
Triggering:- The turning on Process of the SCR is known as Triggering. In other words, turning the SCR from Forward-Blocking state to Forward-Conduction state is known as Triggering.
Which triggering is the most reliable?
Gate triggering process is the most reliable as junction temperature does not rise to high value in this process.
What is meant by TRIAC?
A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three terminal electronic component that conducts current in either direction when triggered. The bidirectionality of TRIACs makes them convenient switches for alternating-current (AC).
Which is more latching current or holding current of an SCR and why?
Latching Current and Holding Current Ratio Generally, latching currents are higher than the holding currents used for high rating thyristors.
What’s the difference between a holding current and a latching current?
The difference between a holding current and a latching current in SCR mainly includes what is a latching current, latching current in SCR, what is a holding current, holding current in SCR, its V-I Characteristics, latching current & holding current ratio and its differences. What is Holding Current?
The latching current is the smallest amount of anode current is required for preserving the thyristor in the ON condition instantly once a thyristor is turned ON then the gate signal has been detached. This current is connected with the process of turning ON.
How does the gate current affect the conduction state?
Depends on the size of the SCR the gate current varies from a few milli-amps to 200 milli amps or more. If the gate current applied is more, then more electrons are injected into the junction J2 and results to come into the conduction state at much lower applied voltage.
When does the gate signal not need to be applied?
Once the SCR start conducting because of positive gate current, the gate current is no longer needed to keep the SCR in conduction mode. The gate signal should not be applied if the SCR is in reverse bias condition. The gate terminal should be more positive with respect to a cathode for turning on of SCR.