In an Op-Amp voltage regulator, the regulating element is connected:

Explanation:

Here's an explanation of why the regulating element is connected in series with the load:

In an Op-Amp voltage regulator circuit, the regulating element is typically connected in series with the load. This arrangement allows the Op-Amp to control the output voltage across the load to maintain a stable voltage level.

Basic Voltage Regulation Principle:

The primary function of a voltage regulator is to maintain a constant output voltage regardless of variations in the input voltage or load conditions. To achieve this, the voltage regulator needs to control the voltage across the load.

Op-Amp Feedback:

Op-Amps are widely used in voltage regulator circuits because they can provide excellent voltage regulation. The Op-Amp compares the output voltage to a reference voltage (usually from a Zener diode or a voltage divider) and adjusts the current through the regulating element (usually a pass transistor) to keep the output voltage at the desired level.

Series Connection:

By connecting the regulating element (pass transistor) in series with the load, the Op-Amp can precisely control the current flowing through the load. When the load tries to draw more current or when the input voltage varies, the Op-Amp adjusts the pass transistor's conductivity to maintain the voltage across the load at the desired level.

Voltage Drop Across Regulating Element:

The voltage drop across the regulating element (pass transistor) is adjusted to ensure that the voltage across the load remains constant. This is how voltage regulation is achieved. If the load resistance or input voltage changes, the Op-Amp responds by changing the pass transistor's conductivity to compensate for these variations.

Connecting the regulating element in series with the load allows the Op-Amp to effectively control the output voltage and ensure stable operation, making option 1) "in series with the load" the correct choice.