# Optimization

# Circuit Optimization Strategies

This page covers practical strategies for optimizing your VIC circuit design using the calculator. Learn how to achieve specific goals like maximizing Q, hitting a target frequency, or optimizing voltage magnification.

## Optimization Goals

Different applications may prioritize different characteristics:

<table id="bkmrk-goal-optimize-for-tr" style="width: 100%; border-collapse: collapse; margin: 20px 0;"><thead><tr style="background: #007bff; color: white;"><th style="padding: 10px; border: 1px solid #ddd;">Goal</th><th style="padding: 10px; border: 1px solid #ddd;">Optimize For</th><th style="padding: 10px; border: 1px solid #ddd;">Trade-offs</th></tr></thead><tbody><tr><td style="padding: 10px; border: 1px solid #ddd;">Maximum Voltage</td><td style="padding: 10px; border: 1px solid #ddd;">High Q, matched resonance</td><td style="padding: 10px; border: 1px solid #ddd;">Narrower bandwidth, critical tuning</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Stable Operation</td><td style="padding: 10px; border: 1px solid #ddd;">Moderate Q, wide bandwidth</td><td style="padding: 10px; border: 1px solid #ddd;">Lower peak voltage</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Frequency Flexibility</td><td style="padding: 10px; border: 1px solid #ddd;">Lower Q, broader response</td><td style="padding: 10px; border: 1px solid #ddd;">Reduced magnification</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Energy Efficiency</td><td style="padding: 10px; border: 1px solid #ddd;">Minimize losses (DCR, R<sub>sol</sub>)</td><td style="padding: 10px; border: 1px solid #ddd;">May require larger components</td></tr></tbody></table>

## Strategy 1: Maximizing Q Factor

Q determines voltage magnification and selectivity. To maximize Q:

#### Reduce Choke DCR:

<div id="bkmrk-use-larger-wire-gaug" style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;">- Use larger wire gauge (lower AWG number)
- Use copper instead of aluminum
- Minimize wire length (fewer turns with higher-μ core)
- Consider Litz wire for high frequencies

</div></div>#### Reduce Solution Resistance:

<div id="bkmrk-increase-water-condu" style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;">- Increase water conductivity slightly (add small amount of electrolyte)
- Increase electrode area
- Decrease electrode gap (but watch capacitance change)
- Ensure good electrode contact

</div></div>#### Increase L or Decrease C:

<div id="bkmrk-higher-l%2Fc-ratio-rai" style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;">- Higher L/C ratio raises Z₀ = √(L/C)
- Q = Z₀/R, so higher Z₀ means higher Q
- Must maintain same f₀ = 1/(2π√LC)

</div>#### Q Factor Relationships:

Q = 2πf₀L/R = Z₀/R = √(L/C)/R

To double Q: halve R, or quadruple L (while quartering C to maintain f₀)

## Strategy 2: Hitting Target Frequency

When you need a specific resonant frequency:

#### Approach A: Fixed L, Adjust C

<div id="bkmrk-design-or-select-cho" style="background: #e7f3ff; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #e7f3ff; padding: 20px; border-radius: 5px; margin: 20px 0;">1. Design or select choke for desired L
2. Calculate required C: C = 1/(4π²f₀²L)
3. If C<sub>wfc</sub> ≠ required C: 
    - Add parallel capacitor if C<sub>wfc</sub> is too low
    - Modify electrode geometry if adjustment is large

</div></div>#### Approach B: Fixed C, Adjust L

<div id="bkmrk-measure-or-calculate" style="background: #e7f3ff; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #e7f3ff; padding: 20px; border-radius: 5px; margin: 20px 0;">1. Measure or calculate WFC capacitance
2. Calculate required L: L = 1/(4π²f₀²C)
3. Design choke for that inductance

</div></div>#### Approach C: Adjust Both

<div id="bkmrk-start-with-practical" style="background: #e7f3ff; padding: 20px; border-radius: 5px; margin: 20px 0;">1. Start with practical component ranges
2. Use calculator to explore L/C combinations
3. Choose combination that also optimizes Q

</div>### Fine-Tuning Frequency

<table id="bkmrk-adjustment-effect-on" style="width: 100%; border-collapse: collapse; margin: 20px 0;"><thead><tr style="background: #28a745; color: white;"><th style="padding: 10px; border: 1px solid #ddd;">Adjustment</th><th style="padding: 10px; border: 1px solid #ddd;">Effect on f₀</th><th style="padding: 10px; border: 1px solid #ddd;">Typical Range</th></tr></thead><tbody><tr><td style="padding: 10px; border: 1px solid #ddd;">Add parallel capacitor</td><td style="padding: 10px; border: 1px solid #ddd;">Decreases f₀</td><td style="padding: 10px; border: 1px solid #ddd;">1-50 nF typical</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Adjust core gap (if gapped)</td><td style="padding: 10px; border: 1px solid #ddd;">Changes L → changes f₀</td><td style="padding: 10px; border: 1px solid #ddd;">±20% L adjustment</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Add/remove turns</td><td style="padding: 10px; border: 1px solid #ddd;">Changes L significantly</td><td style="padding: 10px; border: 1px solid #ddd;">L ∝ N²</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Change water level</td><td style="padding: 10px; border: 1px solid #ddd;">Changes C → changes f₀</td><td style="padding: 10px; border: 1px solid #ddd;">Proportional to area</td></tr></tbody></table>

## Strategy 3: Matching Primary to Secondary

For maximum energy transfer, align primary and secondary resonances:

#### Exact Match (f₀<sub>pri</sub> = f₀<sub>sec</sub>):

<div id="bkmrk-maximum-voltage-tran" style="background: #fff3cd; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #fff3cd; padding: 20px; border-radius: 5px; margin: 20px 0;">- Maximum voltage transfer at resonance
- Narrow combined response
- Requires precise tuning

</div></div>#### Slight Offset (5-10% difference):

<div id="bkmrk-broader-frequency-re" style="background: #fff3cd; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #fff3cd; padding: 20px; border-radius: 5px; margin: 20px 0;">- Broader frequency response
- More tolerant of drift
- Slightly reduced peak transfer

</div></div>#### Calculator Approach:

<div id="bkmrk-design-secondary-%28l2" style="background: #fff3cd; padding: 20px; border-radius: 5px; margin: 20px 0;">1. Design secondary (L2 + WFC) first—this is usually more constrained
2. Calculate secondary f₀
3. Select C1 to tune primary to match: C1 = 1/(4π²f₀²L1)
4. Verify with simulation

</div>## Strategy 4: Optimizing for Available Components

When working with existing components:

#### Step 1: Characterize What You Have

<div id="bkmrk-measure-l-of-availab" style="background: #f8f9fa; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #f8f9fa; padding: 20px; border-radius: 5px; margin: 20px 0;">- Measure L of available chokes
- Measure C of your WFC
- Note DCR values

</div></div>#### Step 2: Calculate Natural Resonance

f₀ = 1/(2π√LC)

This is where your circuit wants to resonate.

#### Step 3: Evaluate Performance

<div id="bkmrk-is-f%E2%82%80-in-your-driver" style="background: #f8f9fa; padding: 20px; border-radius: 5px; margin: 20px 0;"><div style="background: #f8f9fa; padding: 20px; border-radius: 5px; margin: 20px 0;">- Is f₀ in your driver's range?
- Is Q acceptable at this frequency?
- Are there SRF issues?

</div></div>#### Step 4: Adjust as Needed

<div id="bkmrk-add-tuning-capacitor" style="background: #f8f9fa; padding: 20px; border-radius: 5px; margin: 20px 0;">- Add tuning capacitor if f₀ is too high
- Consider different choke if f₀ is way off
- Accept the natural f₀ if performance is good

</div>## Sensitivity Analysis

Understanding how sensitive your design is to variations:

<table id="bkmrk-parameter-change-eff" style="width: 100%; border-collapse: collapse; margin: 20px 0;"><thead><tr style="background: #17a2b8; color: white;"><th style="padding: 10px; border: 1px solid #ddd;">Parameter Change</th><th style="padding: 10px; border: 1px solid #ddd;">Effect on f₀</th><th style="padding: 10px; border: 1px solid #ddd;">Effect on Q</th></tr></thead><tbody><tr><td style="padding: 10px; border: 1px solid #ddd;">L +10%</td><td style="padding: 10px; border: 1px solid #ddd;">f₀ -5%</td><td style="padding: 10px; border: 1px solid #ddd;">Q +5%</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">C +10%</td><td style="padding: 10px; border: 1px solid #ddd;">f₀ -5%</td><td style="padding: 10px; border: 1px solid #ddd;">Q -5%</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">R +10%</td><td style="padding: 10px; border: 1px solid #ddd;">No change</td><td style="padding: 10px; border: 1px solid #ddd;">Q -10%</td></tr><tr><td style="padding: 10px; border: 1px solid #ddd;">Temperature +10°C</td><td style="padding: 10px; border: 1px solid #ddd;">f₀ +2% (due to ε<sub>r</sub> drop)</td><td style="padding: 10px; border: 1px solid #ddd;">Q +5% (R<sub>sol</sub> drops)</td></tr></tbody></table>

## Common Optimization Mistakes

#### ❌ Chasing Extreme Q

Very high Q makes the circuit sensitive to drift and hard to tune. Q of 50-100 is often more practical than Q &gt; 200.

#### ❌ Ignoring SRF

A design that works on paper fails if operating frequency is too close to SRF. Always check this!

#### ❌ Forgetting Water Resistance

Solution resistance often dominates losses. Pure distilled water has higher resistance than you might expect.

#### ❌ Not Accounting for Parasitics

Real circuits have stray inductance and capacitance. Leave margin for these effects.

#### ❌ Over-constraining the Design

If you fix too many parameters, you may have no degrees of freedom for optimization.

## Optimization Checklist

<div id="bkmrk-%E2%98%90-define-your-primar" style="background: #d4edda; padding: 20px; border-radius: 5px; margin: 20px 0;">1. ☐ Define your primary optimization goal
2. ☐ Identify fixed constraints (available components, frequency range)
3. ☐ Calculate baseline performance
4. ☐ Identify largest loss contributor (DCR vs R<sub>sol</sub>)
5. ☐ Make targeted improvements to dominant loss
6. ☐ Verify SRF is &gt;3× operating frequency
7. ☐ Check that primary/secondary are reasonably matched
8. ☐ Run simulation to verify improvements
9. ☐ Consider sensitivity to variations
10. ☐ Document final design parameters

</div>**Remember:** Optimization is iterative. The calculator makes it easy to try variations quickly. Don't expect to find the optimal design on the first try—explore the design space!

*Next: Interpreting Calculation Results →*