TSI Pass Node
True Strength Index — Series Input
Overview
The TSI Pass Node computes the True Strength Index on a series input. TSI double-smooths the price change and the absolute price change using two consecutive EMAs, then divides to create a normalized momentum oscillator bounded in [−100, +100].
Developed by William Blau, TSI applies double exponential smoothing to filter out noise from raw price changes — making it less susceptible to whipsaws than single-smoothed momentum oscillators. The slow and fast parameters control the two EMA stages independently, allowing flexible tuning between responsiveness and stability.
Formula
Parameters
| Parameter | Default | Description |
|---|---|---|
| slow | 25 | Period for the outer (slow) EMA smoothing stage |
| fast | 13 | Period for the inner (fast) EMA smoothing stage |
Inputs & Outputs
| Slot | Direction | Type | Description |
|---|---|---|---|
| input | Input | { values, timestamps } | Price or any numeric series |
| values | Output | (number | null)[] | TSI values in [−100, +100]; nulls during warm-up |
| timestamps | Output | number[] | Unix timestamps aligned to input |
Use Cases
Zero-Line Trend Signals
TSI crossing above zero signals bullish momentum; crossing below signals bearish. Because TSI is double-smoothed, zero-line crossings produce fewer false signals than single-smoothed oscillators. A zero-cross is a quality trend-change signal.
Signal Line Crossovers
Add a signal line (EMA of TSI, typically 7–13 periods) using a downstream EMA Pass node. TSI crossing above its signal line generates buy signals; crossing below generates sell signals — analogous to MACD signal-line crossovers.
Divergence Analysis
TSI's smooth output makes divergence patterns easier to identify than noisier oscillators. Price making higher highs with TSI making lower highs is a high-quality bearish divergence signal, particularly effective on daily timeframes.
Tips & Best Practices
Slow vs Fast Balance
The default (25, 13) provides a good balance between smoothness and responsiveness. For short-term trading, try (13, 7). For position trading and less noise, try (40, 20). Always keep slow > fast.
Slower to React Than RSI
TSI is considerably slower than RSI due to double smoothing. It will miss short-term price spikes but handles sustained momentum moves better. If you need faster signals, reduce both periods proportionally or use RSI Pass instead.
+25/−25 Overbought/Oversold
Unlike RSI's 30/70, TSI uses approximately +25 (overbought) and −25 (oversold) as thresholds — though these vary by instrument. In strongly trending markets, TSI can remain above +25 or below −25 for extended periods.