1. What is PCB Spacing Calculator with Allowance?

Definition: This calculator determines the minimum required spacing between PCB traces based on peak voltage and an additional safety allowance.

Purpose: It helps PCB designers ensure proper electrical isolation and prevent arcing or short circuits in electronic circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Required spacing (mm)
• \( V_{peak} \) — Peak voltage between traces (volts)
• \( A \) — Additional safety allowance (mm)

Explanation: The base spacing of 0.6mm plus 0.005mm per volt accounts for basic clearance needs, while the allowance provides additional safety margin.

3. Importance of Proper PCB Spacing

Details: Correct spacing prevents electrical breakdown, reduces crosstalk, and ensures compliance with safety standards like IPC-2221.

4. Using the Calculator

Tips: Enter the peak voltage between traces and your desired safety allowance (default 0.2mm). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the purpose of the allowance?
A: The allowance provides extra safety margin for manufacturing tolerances, environmental factors, and unexpected voltage spikes.

Q2: Is this formula suitable for high voltage applications?
A: For voltages above 500V, consult specific high-voltage design guidelines as the relationship may become non-linear.

Q3: How do I determine peak voltage?
A: Peak voltage is the maximum potential difference between adjacent traces, including any transients or spikes.

Q4: What's a typical allowance value?
A: Common allowances range from 0.1mm to 0.5mm depending on application criticality and manufacturing capabilities.

Q5: Does this account for environmental factors?
A: No, for high humidity or contaminated environments, consider increasing the allowance or using conformal coating.