DIY Sawtooth Wave Generator Circuit and Working

A sawtooth waveform is a sort of linear, non-sinusoidal waveform with a triangular form during which the rise time and fall time are completely different. A pure triangular waveform can also be linear and non-sinusoidal, but it surely has equal rise and fall occasions. The sawtooth waveform may also be referred to as an uneven triangular wave.

Sawtooth waveforms might be generated by integrating sq. waves with unequal rise and fall occasions (asymmetrical sq. waves). Triangular waveforms and sawtooth waveforms are utilized in purposes like thyristor (SCR, triac, and many others) switching, sampling, tone/frequency technology, modulation, and many others. A sawtooth wave generator utilizing the NE555 timer is introduced right here. The prototype examined in EFY lab is proven in Fig. 1.

Fig. 2 reveals the circuit diagram of the sawtooth wave generator. The guts of the circuit is the NE555 timer IC, which is used for producing the sawtooth waves. This can be a quite simple and cheap circuit for producing sawtooth waveforms. Usually, UJT-based leisure oscillators are used, however they don’t seem to be freely out there and are additionally costly.

PART LIST
Semiconductors:
IC1	-555/NE555 timer IC
D1	-1N4148 sign diode
Resistors (all 1/4-watt, ±5% carbon):
R1	-56-kilo-ohm
R2	-1-kilo-ohm
R3	-10-kilo-ohm
VR1	-100-kilo-ohm potentiometer
Capacitors:
C1	-100μF, 35V electrolytic
C2-C5	-0.1µF ceramic disk
Miscellaneous:CON1, CON2	-2-pin connector

This circuit makes use of simply the NE555 timer IC and some passive elements. We all know that the NE555 timer IC is mostly used to generate a sq. wave sign. However with slight modifications on the output, sawtooth waveform technology is feasible.

The IC NE555 is wired as an astable multivibrator with unequal on and off occasions. The resistors R1 and R2 and capacitor C3 set the on and off time intervals. The values of those elements are such that the off time is lower than the on time.

When the ability provide is switched on, capacitor C3 begins charging by means of resistors R1 and R2. When the voltage throughout C3 rises above 2/3Vcc, the higher comparator contained in the NE555 swings to optimistic saturation, triggering the inner flip-flop. This makes the output pin 3 of the timer go excessive. Now capacitor C3 begins to discharge by means of resistor R2 into pin 7 of the IC.

When the voltage throughout capacitor C3 turns into lower than 1/3Vcc, the decrease comparator contained in the IC switches to optimistic saturation, triggering the inner flip-flop once more. Because of this, the output of the timer at its pin 3 goes low. This motion is repeated, leading to a sq. wave at pin 3 of the NE555. The charging time (on time) is given by the equation T1= 0.69(R1+R2)C3, and the discharging time (off time) is given by the equation T2=0.69R2C3.

This sq. wave output at pin 3 of the NE555 is additional processed by means of potentiometer VR1, resistor R3, sign diode 1N4148 (D1), and capacitors (C4, C5) to acquire a sawtooth sign throughout CON2. Potentiometer VR1 might be adjusted to get the utmost output of the sawtooth wave.

Assemble the circuit on a breadboard or a general-purpose PCB and enclose it in a small cupboard. Repair CON1 on the rear facet of the field and join a 12V battery or adaptor for the ability provide. Join CON2 on the entrance of the field for utilizing the sawtooth output. Now the sawtooth generator is able to use.

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Pradeep G. is an electronics designer primarily based in Cochin, Kerala. His areas of curiosity are digital, opto electronics, wi-fi communications and distant management initiatives and all forms of sensor primarily based initiatives.