There is equipment and devices that are not only powered by the mains, but also in which the mains serves as a source of such impulses necessary for the operation of the device circuit. When such devices are powered from the mains with a different frequency or from an autonomous source, a problem arises with where to get the clock frequency from.

The clock frequency in such devices is usually either equal to the mains frequency (60 or 50 Hz) or equal to twice the mains frequency when the clock source in the device circuit is a bridge rectifier circuit without a smoothing capacitor.

Below are four circuits of 50 Hz, 60 Hz, 100 Hz and 120 Hz frequency pulse generators based on the CD4060B chip and a 32768 Hz clock quartz resonator.

Generator circuit at 50 Hz

Rice. 1. Schematic diagram of a signal generator with a frequency of 50 Hz.

Figure 1 shows a 50 Hz frequency generator circuit. The frequency is stabilized by a Q1 quartz resonator at 32768 Hz, from its output inside the D1 chip, the pulses are sent to a binary counter. The frequency division factor is set by diodes VD1-VD3 and resistor R1, which reset the counter every time its state reaches 656. At the same time, 32768 / 656 = 49.9512195.

It's not quite 50Hz, but very close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the crystal oscillator and get a result closer to 50 Hz.

Generator circuit at 60 Hz

Figure 2 shows a 60 Hz frequency generator circuit. The frequency is stabilized by a Q1 quartz resonator at 32768 Hz, from its output inside the D1 chip, the pulses are sent to a binary counter.

Rice. 2. Schematic diagram of a signal generator with a frequency of 60 Hz.

The frequency division factor is set by diodes VD1-VD2 and resistor R1, which reset the counter every time its state reaches 544. At the same time, 32768 / 544 = 60.2352941. It's not exactly 60Hz, but close.

In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the crystal oscillator and get a result closer to 60 Hz.

Generator circuit at 100 Hz

Figure 3 shows a 100 Hz frequency generator circuit. The frequency is stabilized by a Q1 quartz resonator at 32768 Hz, from its output inside the D1 chip, the pulses are sent to a binary counter. The frequency division factor is set by diodes VD1-VD3 and resistor R1, which reset the counter every time its state reaches 328. At the same time, 32768 / 328 = 99.902439.

Rice. 3. Schematic diagram of a signal generator with a frequency of 100 Hz.

It's not exactly 100Hz, but close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the crystal oscillator and get a result closer to 100 Hz.

Generator at 120 Hz

Figure 4 shows a diagram of a 120 Hz frequency generator. The frequency is stabilized by a Q1 quartz resonator at 32768 Hz, from its output inside the D1 chip, the pulses are sent to a binary counter. The frequency division factor is set by diodes VD1-VD2 and resistor R1, which reset the counter every time its state reaches 272. At the same time, 32768 / 272 = 120.470588.

It's not exactly 120Hz, but close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the crystal oscillator and get a result closer to 120 Hz.

Rice. 4. Schematic diagram of a signal generator with a frequency of 120 Hz.

The power supply voltage can be from 3 to 15V, depending on the supply voltage of the circuit, or rather, on the required value of the logic level. The output pulses in all circuits are asymmetric, this must be taken into account in their specific application.

One minute pulse shaper

Figure 5 shows a circuit for a pulse shaper with a period of one minute, for example, for an electronic digital clock. The input receives a signal with a frequency of 50 Hz from the mains through a transformer, voltage divider or optocoupler, or from another source of frequency 50 Hz.

Resistors R1 and R2, together with the inverters of the D1 chip, designed for the clock generator circuit, form a Schmitt trigger, so you don’t have to worry about the shape of the input signal, it can be a sinusoid.

Fig.5. Pulse shaper circuit with a period of one minute.

With diodes VD1-VD7, the counter division ratio is limited to 2048 + 512 + 256 + 128 + 32 + 16 + 8 = 3000, which, at an input frequency of 50 Hz at pin 1 of the microcircuit, gives pulses with a period of one minute.

Additionally, you can take pulses with a frequency of 0.781 Hz from pin 4, for example, to set the hour and minute counters to the current time. The voltage of the power supply can be from 3 to 15V, depending on the supply voltage of the electronic clock circuit, or rather, on the required value of the logic level.

Snegirev I. RK-11-16.

The 555 integrated timer chip was developed 44 years ago in 1971 and is still popular today. Perhaps no microcircuit has served people for so long. What they didn’t collect on it, they even say that the number 555 is the number of options for its application :) One of the classic applications of the 555 timer is an adjustable square-wave generator.
This review will describe the generator, the specific application will be next time.

The board was sent sealed in an antistatic bag, but the microcircuit is very oaky and it is not so easy to kill it with static.


Mounting quality is normal, the flux is not washed




The generator circuit is standard for obtaining a duty cycle of pulses ≤2

The red LED is connected to the generator output and at a low output frequency it blinks.
According to Chinese tradition, the manufacturer forgot to put a limiting resistor in series with the top trimmer. According to the specification, it must be at least 1 kOhm so as not to overload the internal key of the microcircuit, however, in reality, the circuit also works with lower resistance - up to 200 Ohm, at which generation is disrupted. It is difficult to add a limiting resistor to the board due to the layout of the printed circuit board.
The operating frequency range is selected by the installed jumper in one of four positions
The seller indicated the frequencies incorrectly.


Really measured generator frequencies with a supply voltage of 12V
1 - from 0.5Hz to 50Hz
2 - from 35Hz to 3.5kHz
3 - from 650Hz to 65kHz
4 - from 50kHz to 600kHz

The lower resistor (according to the scheme) sets the pulse pause duration, the upper resistor sets the pulse repetition period.
Supply voltage 4.5-16V, maximum output load - 200mA

The stability of the output pulses on the 2nd and 3rd ranges is low due to the use of capacitors made of ferroelectric ceramics of the Y5V type - the frequency creeps away not only when the temperature changes, but even when the supply voltage changes (and at times). I did not draw graphics, just take my word for it.
On other ranges, the pulse stability is acceptable.

That's what he gives out on 1 range
At the maximum resistance of trimmers


In meander mode (upper 300 ohm, lower at maximum)


In maximum frequency mode (upper 300 ohms, lower to minimum)


In the minimum duty cycle mode (upper trimmer at maximum, lower trimmer at minimum)

For Chinese manufacturers: add a 300-390 ohm terminating resistor, replace the 6.8uF ceramic capacitor with a 2.2uF/50V electrolytic capacitor, and replace the 0.1uF Y5V capacitor with a better quality 47nF X5R (X7R)
Here is the completed schematic


I didn’t remake the generator myself, because. These shortcomings are not critical for my application.

Conclusion: the usefulness of the device is found out when any of your homemade products require you to apply impulses to it :)
To be continued…