Signal generator circuit experiment

1. Circuits and circuits

The principle circuit is shown in the figure below.

The circuit uses CD4060 to form a 32768Hz crystal oscillator circuit. Through its built-in 16~16384 frequency division circuit, it can obtain a variety of clock signals from 2 to 2048Hz. At the 2Hz output terminal Q14 of CD4069, a light-emitting diode is connected to display a half-second signal and monitor whether the circuit is working normally. This circuit can be used to provide a clock signal to an external breadboard experimental circuit.

2. Working principle of CD4060 integrated circuit

CD4060 is a 14-bit binary serial counter and oscillator circuit, and its pin arrangement is shown in the figure below. CD4060 consists of two circuits, one is a 14-level frequency division counter circuit, and the other is an oscillator circuit. The frequency divider part is similar to CD4040, with frequency division coefficients of 16~1024 and 4096~16384, which are output by Q4~Q10 and Q12~Q14 respectively; the oscillator part can be composed of two internal NOT gates and external resistors and capacitors to form an RC oscillator, with an oscillation frequency of f=1/2.2RC; an external crystal can also be used to form a high-precision crystal oscillator.

3. Signal generator monitoring experiment

Ground one end of a piezoelectric ceramic and connect the other end to the output of the CD4060 with a breadboard, and you can hear the clock signals of different frequencies generated by each output end.

4.CD4060 expansion experiment

(1) CD40 60 second pulse signal generator circuit experiment

The lowest frequency of CD4060 output is 2Hz, and a second signal can be obtained by dividing it by 2. A CD4040 can be used to divide it by 2 to obtain a second pulse signal of 1Hz.

(2) Timer circuit experiment

CD4060 is widely used in timer circuits.

You can choose oscillators with different frequencies to get output pulse signals with different periods from each of its output terminals. If the period of the signal output by the oscillator is T, you can get a pulse signal with a period of 2c★T at each output terminal, where c=4~10,11~14. By choosing different values ​​of T and c, you can get a timing circuit of any length.

(3) Listen to RF signals

Using the frequency divider principle of this circuit, we can directly feel the RF signal. Connect a ceramic sounding piece to the Q10 output of CD4060, input the medium wave RF signal at the 11th pin, and you can hear the hum of the ceramic sounding piece. The RF signal can be obtained from the local oscillator of the medium wave radio, and the local oscillator signal is connected to the 11th pin of CD4060 through a 10pF capacitor. Similarly, you can listen to the address bus A15~A8 signals of the microcontroller.

(4) Experiment on measuring sound frequency

In the absence of a frequency meter, this circuit can be used to indirectly measure the frequency of sound. By using the frequency division method, the sound frequency can be reduced to a few Hz or even a fraction of a Hz, displayed through a light signal, and then its frequency can be measured with a stopwatch.

5. Expand production

The above CD4060 experimental circuit only uses half of the main breadboard, and the other half can be used to assemble other electronic works. For example, a CD4069 AC signal amplifier can be installed to generate sound using piezoelectric ceramics. This circuit can be used to monitor the working status of the external breadboard experimental circuit.