The last electrocution by electric chair to execute a prisoner without another choice was a lady named Lynda Lyon Block in the year 2002 in Alabama.
However in 2013 there was an execution carried out in the state of Virginia.
The electric chair that was used in executions uses 1,000 or more volts of AC electricity at high amperage to kill the death row inmate.
When an inmate is executed using the electric chair the condemned prisoner is strapped to a wooden chair that has electrodes that attack to the persons feet and head.
Then when the time comes the person throws a switch to send voltage through the persons body and the first throw of the switch should render the person unconscious and then they throw the switch again for another 5 minutes or so and that is supposed to destroy the vital organs and do the actual killing of the inmate.
Usually a sponge that is wet will be placed on the inmates head to allow the inmate to get electrocuted easier and much faster.