There is no shortage of excellent, low-cost exchange-traded funds (ETFs) that specialize in dividend stocks. There are some that focus on stocks that pay above-average dividends, stocks whose dividends grow rapidly,

Stocks that pay quarterly dividends can help protect your portfolio — and supercharge your cash flow — in rocky markets and uncertain times

With volatility spiking and stock market indexes like the S&P 500 (SNPINDEX: ^GSPC) and Nasdaq Composite (NASDAQINDEX: ^IXIC) down on the year, investors may be looking for ways to diversify their portfolios and collect some passive income.

A good example of this comes from some simple math around Schwab U.S. Dividend Equity ETF (NYSEMKT: SCHD), starting with just a $500 investment. What does Schwab U.S. Dividend Equity ETF do? Before getting into the math,