Do I need to draw a circuit to apply for a patent for electronic products?

This depends on where the "improvement point" of your product is. If the improvement mainly involves specific circuits, it is necessary to draw a circuit diagram;

If the improvement is mainly in the product structure, it only shows that it is possible to draw no circuit in the general circuit structure;

If a new product is made, it is related to the function of the circuit, and it can also be expressed in terms similar to "RF module" and "power module".