Signal Annunciators are presented that emit short tones upon being triggered by an electrical signal. They are intended primarily as automotive turn signal and emergency light operation indicators and are designed to be connected downstream of the turn signal switch. They comprise oscillating circuitry and piezoelectric discs. In each, capacitors are used to cause a decay in the volume of the tone produced. In the first species, a capacitor is placed in series with the oscillating circuitry. When a signal voltage is applied to the circuit, the capacitor begins to charge, passing current to the oscillator and disc, which emits sound. As the capacitor charges, less and less current is passed, creating a brief tone of decaying volume. The same effect is created in the second species by placing a smaller capacitor in series with the bias current input of the amplifier in the oscillating circuit. The third species resembles the second, but has a signal input separate from its power supply connections which allows for high input impedance. The devices produce consistent, short, pleasant tones regardless of the length of the input signal, without additional circuitry. They are intrinsically simple and contain very few components. A new case design is also presented for circuit board mounting that allows the sound to be emitted in a direction planar to the circuit board.

A fire exit alert system, preferably integrated into an exit device or automatic fire exit door closer, uses sound and light to signal the location of a fire exit in darkness and smoke-obscured rooms. The alert system includes a voice signal, such as "EXIT LOCATED HERE," to signal that the location of the voice is also the location of the exit. A white noise signal generator is used to supplement the voice signal and produces a sound that is particularly localizable by the human ear. A strobe light and a laser are used to produce a visual guide to the location of the exit. The strobe light is flashed when the word "HERE" is used in the voice signal. The laser is used to produce a cone of light that points towards the fire exit alert system.