Parallel inverter is a type of inverter used to convert DC power into AC power. It operates by switching the DC input voltage across the primary winding of a transformer, which then induces an AC voltage across the secondary winding.

The commutating capacitor, denoted as C, is an important component in the parallel inverter circuit. It is used to control the switching of the DC input voltage across the transformer winding. By charging and discharging at specific intervals, the commutating capacitor allows the inverter to generate an AC voltage waveform.

The correct answer to the given question is option 'A' - the commutating capacitor C is across the primary of the transformer, and the load is across the secondary. This means that the commutating capacitor is connected in parallel with the primary winding of the transformer, while the load (which could be any electrical device or system) is connected across the secondary winding.

The reason for this configuration is as follows:

1. Commutation Process: The commutating capacitor C is responsible for controlling the switching of the DC voltage across the transformer. It charges and discharges at specific intervals to ensure smooth and controlled commutation. Placing the capacitor across the primary winding allows it to directly influence the primary side of the circuit, where the switching action occurs.

2. Transformer Operation: The primary winding of the transformer is where the DC input voltage is switched and converted into an AC voltage. Placing the commutating capacitor across the primary ensures that it affects the switching process directly, enhancing the performance and reliability of the inverter.

3. Load Connection: The load, which is the device or system that receives the AC output voltage, is connected across the secondary winding of the transformer. This arrangement ensures that the load receives the desired AC voltage and current levels.

By connecting the commutating capacitor across the primary winding and the load across the secondary winding, the parallel inverter operates efficiently and effectively. The capacitor aids in smooth commutation, while the load receives the desired AC output. This configuration allows for better control and regulation of the inverter's output, making it suitable for a wide range of applications.

Parallel inverters are electronic devices used to convert direct current (DC) to alternating current (AC). They are commonly used in applications such as uninterruptible power supplies (UPS) and solar power systems. In a parallel inverter, the commutating capacitor and load are connected across the primary of the transformer.

Explanation:
1. What is a parallel inverter?
A parallel inverter is a type of inverter that consists of multiple power electronic switches connected in parallel. These switches are controlled to convert DC power from a source, such as a battery, into AC power that can be used by AC loads.

2. Purpose of the commutating capacitor:
The commutating capacitor, denoted as C, is an essential component in a parallel inverter. It is connected across the primary of the transformer. The main purpose of the commutating capacitor is to provide a path for the commutation of the power electronic switches. Commutation is the process of turning off one switch while turning on another to maintain a continuous AC output voltage.

3. Load connection:
In a parallel inverter, the load is connected across the secondary of the transformer. This means that the AC output voltage is taken from the secondary winding of the transformer and directly connected to the load.

4. Why is the commutating capacitor connected across the primary of the transformer?
The commutating capacitor is connected across the primary of the transformer to provide a low-impedance path for the commutation of the power electronic switches. When a switch turns off, it creates a high voltage spike due to the inductance of the transformer. The commutating capacitor helps to absorb this voltage spike and ensures a smooth transition between the different switches.

5. Advantages of connecting the commutating capacitor across the primary:
- Improved commutation: By connecting the commutating capacitor across the primary, the voltage spikes generated during switch commutation are significantly reduced. This improves the overall performance and reliability of the parallel inverter.
- Lower stress on switches: The commutating capacitor helps to reduce the stress on the power electronic switches by absorbing the high voltage spikes. This extends the lifespan of the switches and improves the efficiency of the inverter.
- Better voltage regulation: The presence of the commutating capacitor across the primary helps to stabilize the output voltage of the inverter, resulting in better voltage regulation for the AC load.

In conclusion, in a parallel inverter, the commutating capacitor is connected across the primary of the transformer, while the load is connected across the secondary. This configuration provides improved commutation, lower stress on switches, and better voltage regulation.