Tone burst generator

Posted on Jan 7, 2013

The tone burst generator supplies a tone for one-half second after the power supply is activated; its intended use is a communications network alert signal. Cessation of the tone is accomplished at the SCR, which shunts the timing capacitor CI charge current when activated. The SCR is gated on when C2 charges up to the gate voltage which occurs in 0.5 seconds. Since only 70 ?? are available for triggering, the SCR must be sensitive enough to trigger at this level.

Tone burst generator
Click here to download the full size of the above Circuit.

The triggering current can be increased, of course, by reducing R2 (and increasing C2 to keep the same time constant). If the tone duration must be constant under widely varying supply voltage conditions, the optional Zener diode regulator circuit can be added, along with the new value for R2 R2' = 82 kfi. If the SCR is replaced by an npn transistor, the tone can be switched on and off at will at the transistor base terminal.

Leave Comment

characters left:

New Circuits



Popular Circuits

1.2 - 15V/3A variable and regulated PS
Adjustable oscillator
Precision-Increasing Buffer
Compact 3-in-1 Stripboard DIYduino with Integrated Sensor and L298N Motor Shield
ecm mic preamplifier
Selfrunning Free Energy 5 KW Kapanadze 1
Reducing the power consumption of the circuit diagram ISO103
A block diagram of AN6657 and basic application circuit