This is Phase locked oscillator circuit,100Hz-10KHz square wave, the other circuit one interesting.
The CMOS IC is selected for this case. It will be Phase Lock Loop IC is CD4046. It hs characteristics the setting circuit as Figure 1.
Using the voltage control frequency. The voltage that is derived from pin 9 of IC1 voltage adjustment of VR1. Including C1 is connected between pin 6 and pin 7 of IC1.
Minimum and a maximum frequency of this circuit are determined by R1 and R2, respectively.
We can generate frequencies from 1 Hz to 1 MHz.
But it must depend on the devices connected to the outside that much.
This creates a cycle frequency from 100 Hz to 10 KHz.
Figure 1 The 100 Hz to 10 KHz square wave generator by Phase Lock Loop IC
For some people, it may seem too little. Would increase the frequency to the next, but do not want to waste more money.
You can add up to the other frequency of about 10 KHz. Just remove R2 from the circuit itself.
Which this R2 determines the frequency in use. By the R2 value of this, would be to refer to R1, it must be 10 times greater than R1.
For R1 and C1 will determine the minimum frequency or low voltage pin 9 of IC1. And at this pin 9 if there is low voltage, the frequency output or at pin 4 of IC1 will be low too.
On the other hand, the pin 9 has high voltage, the output frequency will be higher as well. Understanding is simple enough voltage is proportional to the frequency.
C1 of the circuit, we can change, For the frequency range, we need. See from Table 1. So I like to use bands to choose it.
C1 determine the frequency of use.
C1 (25V) Frequency range
0.1uF 10Hz – 1kHz
0.01uF 100Hz – 10kHz
How to builds
This project is a few components so can assemble on the universal PCB board. But can make a PCB. You should be carefull the polarity of the electrolytic capacitors and IC1 correctly.
Universal tester using 4046
Resistors size ¼W +5%
VR1: 50K__single potentiometer
C1: See text
C2: 0.1uF 50V polyester capacitor
IC1: CD4046___Phase Lock Loop IC
Socket IC 16 pin
Universal PCB board