Accelerator Oscillator

Indicators · Momentum

Bill Williams Accelerator Oscillator — acceleration of the Awesome Oscillator.

The Accelerator Oscillator (AC), another Bill Williams tool, measures the acceleration of momentum — the rate at which the Awesome Oscillator is itself speeding up or slowing down. The logic is that acceleration changes before momentum does, and momentum changes before price does. So the AC is meant to give you the earliest warning in that chain: a heads-up that momentum is about to shift, often a bar or two before the Awesome Oscillator confirms it.

How it works

The block first builds the Awesome Oscillator — SMA(median price, 5) − SMA(median price, 34) using the AO fast SMA (5) and AO slow SMA (34) — then subtracts an SMA of the AO over the AC smoothing SMA (5). That difference is the AC: when it's rising, momentum is accelerating; when falling, decelerating. It plots as a zero-centred histogram in a sub-pane, coloured by direction — Rising (green) when each bar is higher than the last, Falling (red) when lower — and exposes Bull ↑ / Bear ↓ signals on its zero-line crosses.

When to use it

Use the AC as an early momentum-shift filter, almost always alongside other tools rather than alone. Williams's method reads the colour change (two consecutive bars in the new direction) as the early cue and the zero-line cross as confirmation. Because acceleration is the noisiest link in the price→momentum→acceleration chain, the AC fires often and false alarms are common — its value is confirmation timing within a larger system, not standalone signals.

Example

Accelerator Oscillator on EURUSD · H1

Early-confirmation entry: in a system already biased long (200-EMA up), wire bars into the Accelerator Oscillator and require Rising (accelerating up) alongside your entry trigger through an And gate into a Buy Signal — so you only pull the trigger when momentum is actually speeding up. Backtest in the Tester.

Tips & gotchas

• Earliest in the chain — and noisiest. It leads momentum but throws the most false signals; never trade it solo.
• Colour change is the early cue, zero-cross is the confirmation.
• Pairs naturally with the Awesome Oscillator — AO for momentum, AC for its acceleration.
• Best as a filter, adding timing precision to another signal rather than generating entries itself.

Related blocks

• Awesome Oscillator
• Williams Alligator
• MACD
• Momentum

Inputs

Socket	Type	What to wire in
Bars	bars	Price bars

Outputs

Output	Type	Plots as	Description
AC	series	Histogram · sub-pane	Accelerator oscillator
Rising	signal	—	AC higher than the prior bar (green)
Falling	signal	—	AC lower than the prior bar (red)
Bull ↑	signal	Signal arrows	AC crosses above zero
Bear ↓	signal	Signal arrows	AC crosses below zero

Parameters

Parameter	Type	Default	What it does
AO fast SMA	number · 2–100	5
AO slow SMA	number · 3–200	34
AC smoothing SMA	number · 1–100	5
AC color	colour	#26a69a

Chart guides

This indicator draws reference level(s): Zero.

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Reference auto-generated from the block catalog · category Indicators.