Comparison

Smith Charts vs SecondBrain Pro

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Smith Charts

Design matching networks, analyze device parameters, and compute stability circles with this interactive tool. Supports S parameters, various components, and offers advanced engineering features for RF design. Available in dark mode and exportable to PDF.

Highlights
  • Interactive Smith chart with drag and zoom
  • Design matching networks with various components
  • Compute stability, equi gain, and noise circles
  • Import S parameters from Touchstone files
  • Export designs to PDF, image, or file
  • Dark mode support
  • Ruler for wavelength measurement
Features
Read full description

A great experience of the Smith chart. Also in dark mode. Design matching networks, insert S parameters and convert them, or import from touchstone file. Compute stability circles, equi gain and noise circles.  Easy interaction with the Smith chart. This chart can easily replace a physical one, making its use much faster. Smith chart interactivity: - Works on iPhone, iPad and Mac (on Apple Silicon). - Drag and zoom in the chart. - Create multiple Smith Charts and name them. - Switch easily between input and output planes. - Use a ruler and drag it to obtain the wavelength toward generator of a point on the chart, instantly. - Tap the chart to show the coordinates in algebraic notation, you will see also magnitude and phase of that location, and the corresponding impedance. - Insert circles by hand; modify the radius dragging a circle to keep the center in place, or press to translate them and modify the radius keeping the opposite side in place. Then use the padlock button to disable interaction of gestures with circles. - You can also insert a custom circle and a segment in the input and in the output plane, defining its center and radius in a textfield. - Export to file, image or PDF Advanced tools for engineering: Matching networks: - Choose electronic components to design a matching network for your device. - Available components are: L, C, R, Z and lines (transmission line, parallel or series stub, open or shorted). - For each component it is possible to specify the parasites. - For transmission lines, it is possible to choose between Z0, K or L, C representations, and converting between the two (also for parasites). - Tapping on a component it is added to the network and the impedance seen from your device toward the matching network is shown on the smith chart. - You can create a matching network both for input and output planes of the device. - Each network has its own termination (source or load), which can be a one port device or a two ports device where you can choose a termination for the second port. - Each termination can be defined by network parameters (S, Z, Y or h) and the parameters can be imported from a touchstone file. - Components supported: Resistor, Capacitor, Inductor, General impedance (R+jX), Transmission line, Parallel stub, series Stub (both shorted or open). - Each component can be cascaded in series or in parallel, no limits of components. - You can choose a frequency for the impedance calculation and a frequency span for the plot on the Smith Chart. - For S parameters, you can specify a dedicated characteristic impedance, the tool will renormalize the Γ of that termination to be correctly shown on the Smith chart, when the smith chart is defined on a different characteristic impedance. Device analysis: - You can insert the following parameters of a device: network parameters (S, Z, Y or h), specifications (Ga, Gp, Gt, NF), noise data (gamma s optimum noise, minimum NF, rn) and the input/output reflection coefficients. - You can convert network parameters (S, Z, Y, h), and the port type (Γ, Z, Y). - While you are inserting data, you will see the computed results appearing on the chart and on the relative fields. - Results representable on the smith chart: input/output stability circles, power gain and noise circles (equiGa, Gp, Gt, NF circles), reflection coefficients towards load and source and optimum power coefficients. - Other results: obtained power gains and noise (Ga, Gp, Gt, NF) and stability (D, K, kind of stability). - You can display on the Smith chart the input impedance of your component versus frequency (as a function of load impedance) when importing a touchstone file. - For S parameters, you can specify a different characteristic impedance and the tool will automatically convert it to the one defined for the Smith chart, it will let you know the new renormalized parameters.

About

SecondBrain Pro

Features
Read full description

Save a thought while you walk. Find a decision after a meeting. SecondBrain Pro is a voice-first memory app for iPhone and iPad, with an Apple Watch companion for capture from your wrist. Choose local storage or free iCloud sync. Optional Standard and Premium upgrades are one-time purchases. CAPTURE AND RECALL Record a thought or type a note. Organize ideas, learnings, tasks and decisions with tags. Search saved memories by text and dates, or ask AI Chat about your memories when a supported AI provider is available. START FREE Voice and text capture, ordinary search, local storage and iCloud sync are included in Free. On-device AI chat is available on supported Apple Intelligence devices. No SecondBrain account is required. iCloud needs your Apple account and available iCloud storage. STANDARD: OPTIONAL ONE-TIME UPGRADE Add premium speech playback voices, expanded memory context, JSON/Markdown export, and backup and restore tools. iCloud sync is already included in Free. PREMIUM: YOUR OWN BACKEND AND MCP Includes Standard capabilities and adds a connection to your own Cloudflare Worker backend, backend semantic search, API access and MCP integration for compatible tools such as Claude Code and Cursor. This option requires your own Cloudflare account, deployed backend URL and API key. MCP also requires a bridge and compatible client. Cloudflare usage may incur separate charges. Local-only memories are not automatically available to external assistants. WHERE YOUR DATA GOES Local Only stores memories on this device. iCloud sync transfers them through your personal Apple iCloud account. The optional Cloudflare mode sends memories to your configured backend for storage and selected AI processing. Connected MCP clients handle data according to their own configuration and provider policies. Voice capture uses Apple's speech recognition and may use Apple servers. Microphone and speech recognition permission are required. Location context is optional. The app requests in-app consent for AI processing. AI REQUIREMENTS On-device AI chat uses Apple Foundation Models and requires iOS 26 or later, compatible Apple Intelligence hardware, Apple Intelligence enabled and an available model. Voice capture and ordinary search do not depend on Foundation Models. Premium users can configure cloud AI through their own backend. Check the App Store compatibility section before installing. PRICING Free download. Standard and Premium are optional one-time in-app purchases, with no SecondBrain subscription. See the purchase sheet for your regional price and currency. External backend services are separate. Developed in Switzerland by Heinrich Krupp. Product facts: https://secondbrain-pro.netlify.app/facts Support: https://secondbrain-pro.netlify.app/support

Screenshots

Smith Charts4 screens
SecondBrain Pro4 screens

Verdict

The call

The clearest difference is price: SecondBrain Pro at Free against Smith Charts's $3.99. Smith Charts's advantage is in-app purchases (none vs 2) and update cadence (every 3 weeks vs every 2 months). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

SecondBrain Pro is free to download; Smith Charts costs $3.99 up front. SecondBrain Pro sells 2 one-off in-app purchases. Smith Charts asks for nothing beyond the download.

UpkeepUpdate frequency

Smith Charts ships an update every 3 weeks, SecondBrain Pro every 2 months. The most recent releases landed on November 6, 2026 and October 31, 2026 respectively.

Scorecard4 real differences · 6 level
Smith Charts versus SecondBrain Pro: the parameters behind the verdict, then further details
ParameterSmith ChartsSecondBrain Pro
Price$3.99Free — better
Rating3.7 (3 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings3 — better—
Update frequencyEvery 3 weeks — betterEvery 2 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaid—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better17.0
Further details — not scored
Size24 MB10 MB
Age rating4+4+
DeveloperEdoardo OrzesHeinrich Krupp

In-app purchases

None

Smith Charts

No in-app purchases

2 purchases

SecondBrain Pro

One-time2
  • Standard$7.99
  • SecondBrain PREMIUM$17.99

Questions

Is Smith Charts free?
Smith Charts costs $3.99, with no in-app purchases.
Is SecondBrain Pro free?
SecondBrain Pro is free to download, with in-app purchases available.
Do Smith Charts or SecondBrain Pro have ads?
Neither Smith Charts nor SecondBrain Pro shows ads.
Which is updated more often, Smith Charts or SecondBrain Pro?
Smith Charts ships an update every 3 weeks, and SecondBrain Pro every 2 months. Most recently, Smith Charts was updated on November 6, 2026 and SecondBrain Pro on October 31, 2026.

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