Autotransformer and transformer have distinct differences in their symbols used in circuit diagrams and their practical applications. Below, we will discuss these differences in detail.

Symbol Differences

Autotransformer Symbol

The autotransformer symbol is similar to that of an inductor but must include a tap, which indicates its variable transformation ratio. The tap is the key feature distinguishing autotransformers from inductors.

Transformer Symbol

Transformers typically consist of two or more coils and transfer energy through electromagnetic induction. Transformer symbols vary based on their structure and purpose, such as iron-core or air-core transformers.

Symbols of Electrical Transformer

Symbol	Description		Symbol	Description
	Transformer Two windings and an air core Generic symbol			Transformer Two windings and an air core
	Transformer Two windings and an air core			Transformer Two windings and an air core
	Transformer core Fe-Si Laminated core			Transformer with laminated core
	Shielded transformer			Transformer with saturable reactor
	Ferrite core transformer			Variable coupling transformer
	Voltage transformer			Variable coupling transformer
	Single-phase transformer with continuous current regulation			Variable coupling transformer
	Voltage transformer Transformer with voltage regulation			Transformer with moving magnet
	Adjustable transformer core			Adjustable transformer core
	Current transformer Pulse transformer			Current transformer with two cores with a secondary winding on each core
	Current transformer with dual core			Current transformer with three primary conductors
	Current transformer with a secondary winding with a power			Current transformer with two secondary windings on a single core and three primary
	Current transformer with two secondary windings on a core			Low-pass transformer
	High-pass transformer			Single-phase transformer with a shunt winding
	Indicates the polarity of the windings			Transformer with three windings
	Transformer dual voltage

Autotransformer Symbols

	Autotransformers			Autotransformers
	Variable autotransformer Single phase autotransformer with adjustable voltage			Autotransformers
	Variable autotransformer Single phase autotransformer with adjustable voltage			Autotransformer with iron core

Practical Application Differences

Autotransformer Applications

Autotransformers are often used in applications where electrical isolation between the primary and secondary is not required, such as voltage adjustment and motor starting. They are also widely used in high-voltage power systems due to their low cost and high efficiency.

Autotransformer Application Examples

• Voltage Adjustment: Used to adjust voltage levels in AC circuits.
• Motor Starting: Used in autotransformer reduced-voltage starters for three-phase motors.

Transformer Applications

Transformers are primarily used in applications requiring voltage step-up or step-down and electrical isolation, such as power transmission and electronic device power supplies. Transformers provide electrical isolation between the primary and secondary, ensuring safety and reliability.

Transformer Application Examples

• Power Transmission: Used to increase or decrease voltage to match different loads.
• Electronic Device Power Supplies: Provide the appropriate voltage level for electronic devices.

In summary, autotransformer and transformers have distinct differences in their symbols and practical applications. Autotransformers are suitable for applications without electrical isolation requirements, while transformers provide electrical isolation and are widely used in power transmission and electronic device power supplies. Understanding these differences allows engineers to choose the appropriate device for specific application needs.