How to generate 1 clock pulse per hour

1 second clock pulse

can pulse per hour be generated using multivibrator practically ?

how to generate 1 sec from the microcontroller

Yes, but it's not practical.
Large resistance value and large capacior value could give you very innacurate time base of one hour, but its much easier (and cheaper) to use divider and higher clock rate. For example one could use resistor in MΩ range with capacitor of few mF with CMOS version of 555 timing IC or use 4060 CMOS with much shorter time base and built in oscillator. Adding couple more IC's coud allow you to use standard 32768Hz resonators. Replacing those IC's with microcontroller like Microchip's 10F series would give you flexibility of programmable device and bring down cost to resonator and MCU.

how to generate accurate pulse

Yes, in principle, you can build the CMOS multivibrator, either on CMOS logic, FET transistors, or CMOS timer (like TLC7555).

However, you will get the big problems:
1. Firstly, how can you calibrate this circuit, as it changes it status only once per hour, surpose you need to count 10 pulses to calibrate circuit, so will you spend all day long just to stare at the circuit????

2. In general, for this circuit, you have to use large value resistors and polar capacitors, their values change significantly by time and temperature, on the other hand, large polar capacitors have large leakage current, so it may be impossible for you to adjust the circuit.

So, the better solutions are, in my opinion and experiences:
1. If you do not need an accurate pulse, so just build a RC multivibrator on either logic ICs, transistors, or most popular component - timer LM555, with the frequency of hundreds thousand to millions hertz. It is much more easier for you to adjust and calibrate the frequency with a frequency meter.

Next, this frequency is divided by a divider made of either TTL or CMOS logic. This is a hardware divider, so, once you have the right oscillation frequency, you will get the accurate output pulse.

2. If you want an accurate pulse, so replace the above RC multivibrator with a crystal multivibrator. Or consider to design the whole circuit with a microcontroller and crystal.

Hope clear enough for you.
nguyennam

how to generate 1 sec pulse

I'm agree with nguyennam, if you don't need an accurate pulse you must use the option of nguyennam's post. Otherwise you must consider using a uC in your circuit.

By,

GuillerMo (AR)

clock 1 hour pulse

from NE555 and NE556 applications - Philips Semiconductors

Long Time Delays

In the 556 timer the timing is a function of the charging rate of the external capacitor. For long time delays, expensive capacitors with extremely low leakage are required. The practicality of the components involved limits the time between pulses to around twenty minutes.

To achieve longer time periods, both halves may be connected in tandem with a “divide-by” network in between. The first timer section operates in an oscillatory mode with a period of 1/fO. This signal is then applied to a “divide-by-N” network to give an output with the period of N/fO. This can then be used to trigger the second half of the 556. The total time is now a function of N and fO.

Click to expand...

how to generate clock pulse

Here is an example on how to generate 1 second pulse every 240 minutes using "the simplest" microcontroller, namely PICAXE-08 ..


I leave judgment to you ..

Regards,
IanP