What happens to an SCR when you connect positive to the anode and negative to the cathode while shorting the gate and anode?

When a silicon controlled rectifier (SCR) has its anode connected to a positive voltage and the cathode to a negative voltage, with the gate shorted to the anode, it will enter a conducting state, effectively allowing current to flow from the anode to the cathode. This occurs because the gate, which is typically used to control the SCR's switching behavior, is receiving sufficient voltage to trigger the device into conduction when connected in this manner.

In this state, the SCR can be described as going to near "short," meaning that it presents a very low resistance between the anode and cathode. The SCR is designed to remain in this conducting state once triggered, even if the gate is no longer receiving a triggering signal. Therefore, the device will allow a high amount of current to pass through, and the resistance between the anode and cathode will be very low, similar to a closed switch or short.

The other scenarios, like the SCR staying open or becoming high resistance, would not accurately describe the behavior under the specified conditions since it would not be able to conduct with a positive anode and negative cathode without being triggered appropriately. The potential for burning out would also depend on the current levels and heat dissipation,