Simple variable frequency oscillator
This is a very simple circuit utilising a 555 timer IC to generate square wave of frequency that can be adjusted by a potentiometer.
With values given the frequency can be adjusted from a few Hz to several Khz.
To get very low frequencies replace the 0.01uF capacitor with a higher value.
The formula to calculate the frequency is given by:
1/f = 0.69 * C * ( R1 + 2*R2)
The duty cycle is given by:
% duty cycle = 100*(R1+R2)/(R1+ 2*R2)
In order to ensure a 50% (approx.) duty ratio, R1 should be very small when
compared to R2. But R1 should be no smaller than 1K.
A good choice would be, R1 in kilohms and R2 in megaohms. You can then select C
to fix the range of frequencies.
Title: Simple variable frequency oscillator
electronic circuit
Source: www.electroniccircuitsdiagrams.com
Published on: 20050201
Reads: 3819
Print version:
Other electronic circuits and schematics from Oscillators and timers

1KHz Sinewave Generator

Headlights Timer

Lowdistortion Audiorange Oscillator

Sawtooth wave generator

Precision Metronome and Pitch generator

Simple IF Signal Generator

Jogging Timer

Reverse Bias Oscillator

28 LED Clock Timer

9 Second Digital Readout Countdown Timer