Nate Electrical Practice Exam

What does wiring two silicon-controlled rectifiers in reverse parallel allow?

1. Current flow in both directions

2. Current flow from the anode to the gate

3. Current flow from the cathode to the gate

4. Current flow in one direction only

The correct answer is: Current flow in both directions

Wiring two silicon-controlled rectifiers (SCRs) in reverse parallel configuration allows for current flow in both directions. This arrangement enables each SCR to conduct current during opposite half-cycles of an alternating current (AC) waveform. When one SCR is forward-biased (allowing current to flow through it), the other SCR is reverse-biased and blocks current. During the next half-cycle, the roles reverse. This setup is particularly beneficial in AC applications where control of multiple phases or directions of current flow is needed. By utilizing both SCRs, the circuit can handle the entire waveform, providing effective control and protection in various applications, such as in motor drives or power conversion systems. The other options describe scenarios that do not accurately reflect the functionality or characteristics of SCRs in a reverse parallel configuration.