Schematic annotation in PCB Design - Cell-by-Cell Formula Trace

Sample Data

This data represents a list of schematic components with their initial unannotated references and values before annotation.

Cell	Value
A1	Component
B1	Reference
C1	Value
A2	Resistor
B2	R?
C2	10k
A3	Capacitor
B3	C?
C3	100nF
A4	LED
B4	D?
C4	Green
A5	Microcontroller
B5	U?
C5	ATmega328P

Formula Trace

Assign unique reference designators by replacing '?' with incremental numbers per component type

Step 1: Identify all components with reference containing '?'

Step 2: Assign numbers starting from 1 for each component type

Step 3: Replace '?' in references with assigned numbers

Step 4: Update the reference column with new designators

Cell Reference Map

   A          B       C
1 Component  Reference Value
2 Resistor   R?      10k
3 Capacitor  C?      100nF
4 LED        D?      Green
5 Microcontroller  U?      ATmega328P

References B2:B5 contain '?' to be replaced.

The formula uses the Reference column cells B2 to B5 which contain placeholders '?' to assign unique numbers.

Result

   A          B       C
1 Component  Reference Value
2 Resistor   R1      10k
3 Capacitor  C1      100nF
4 LED        D1      Green
5 Microcontroller  U1      ATmega328P

All references now have unique designators.

After annotation, each component has a unique reference designator replacing the '?' with a number.

Sheet Trace Quiz - 3 Questions

What does the '?' symbol in the Reference column represent before annotation?

A A component value

B A completed reference designator

C A placeholder for a unique number

D A component type

Key Result

Replace '?' in reference designators with incremental numbers per component type to ensure uniqueness.