Investopedia

Encyclopedic wood species reference. Properties, workability, and identification for hundreds of species.

Database of radio signals. Identify unknown transmissions by their sound and waterfall pattern.

Investment advice inspired by John Bogle. Forum for passive, low-cost investing.

Personal finance simulator. Model different scenarios for retirement, investments, and life decisions.

Free electrical engineering education. Textbooks, worksheets, calculators, and community forums.

Backtest and analyze investment portfolios. Monte Carlo simulation and factor analysis.