Timers

from

http://wayback.archive.org/web/*/http://uk.geocities.com/ronj_1217/c4060s.html



The Cmos 4060 is a 14-bit binary counter. However - only ten of those bits are connected to output pins. The remaining bits - Q1, Q2, Q3 and Q11 - do exist. You just can't reach them.

The 4060 also has two inverters - connected in series across pins 11, 10 & 9. Together with R3, R4, R5 and C3 - they form a simple oscillator.

While the oscillator is running - the 14-bit counter counts the number of oscillations - and the state of the count is reflected in the output pins.

By adjusting R4 you can alter the frequency of the oscillator. So you can control the speed at which the count progresses. In other words - you can decide how long it will take for any given output pin to go high.

When that pin goes high - it switches the transistor - and the transistor in turn operates the relay.

In single-shot mode - the output pin does a second job. It uses D1 to disable the oscillator - so the count stops with the output pin high.

If you want to use the timer in repeating mode - simply leave out D1. The count will carry on indefinitely. And the output pin will continue to switch the transistor on and off - at the same regular time intervals.


Using "Trial and Error" to set a long time period would be very tedious. A better solution is to use the Setup tables provided - and calculate the time required for Pin 7 to go high. The Setup tables on both schematics are interchangeable. They're just two different ways of expressing the same equation.

For example, if you want a period of 9 Hours - the Range table shows that you can use the output at Pin 2. You need Pin 2 to go high after 9 x 60 x 60 = 32 400 seconds. The Setup table tells you to divide this by 512 - giving about 63 seconds. Adjust R4 so that the Yellow LED lights 63 seconds after power is applied. This will give an output at Pin 2 after about 9 Hours.



Ideally C3 should be non-polarized - but a regular electrolytic will work - provided it doesn't leak too badly in the reverse direction. Alternatively - you can simulate a non-polarized 10uF capacitor by connecting two 22uF capacitors back to back - as shown.

If you need a longer period than 24-hours - increase the value of C3.

The reset button is optional - but it should NOT be used during setup. The time it takes for the Yellow LED to light MUST be measured from the moment power is applied.

Although R1, R2 and the two LEDs help with the setup - they are not necessary to the operation of the timer. If you want to reduce the power consumption - disconnect them once you've completed the setup.

The timers were designed for a 12-volt supply. However - provided a suitable relay is used - both circuits will work at anything from 5 to 15-volts. Applying power starts the timer. And it can be reset at any time by a brief interruption of the power supply.

OR



This circuit uses just two CMOS IC's, a 4011 quad 2 input NAND gate, and a 4020 14-stage ripple binary counter. At switch on R2 and C2 provide a brief reset pulse, which will ensure the output pin Q1 of the 4020 is high. Gates U1 and U2 form a simple astable R1 and C1 determining the timing period. The tolerances of capacitors vary widely, so for more control, you may use a 470n capacitor for C1 and use a fixed 3.3M resistor in series with a 250k preset for R1. A timing period of just less than 1.76seconds is required.

The output of the oscillator at U2 drives the input of the 14-stage ripple counter, U3. The outputs divide sequentially by two and the output signal is taken from Q13, requiring 2048 input pulses before the signal becomes high.

When the output Q13 goes high, the output sounder will become active. Gate U4 of the 4011 is used to "modulate" the output sounder. As U4 is also connected to the output of U2, the output sounder will turn on and off at the same rate as the oscillator.

Suitable output sounders can be found at Maplin Electronics part code KU56L or CR34M. These are self contained DC piezo buzzers, requiring 10mA at 12V DC but work with supply voltages from 3 to 15 Volts DC.

One hour or 3600 seconds divided by 2048 pulses (Q13) requires a timed period of 1.7578 seconds. The timing for a CMOS oscillator, varies with supply voltage, but is approximately 1.1 RC. To achieve the timed period, C1 is 0.47u and R1 is made from a fixed 3.3M resistor in series with a 250k preset.

To adjust this value, connect a low current LED and fixed 2.2k resistor to the output of IC2. The LED should illuminate on each pulse. Adjust the 250k preset until the LED flashes about 34 times per minute (60/34 = 1.76s). If you would like to use this a parking meter timer, then set the unit to trigger before the hour is up or start the timer before you feed the meter to allow extra time.

from

http://www.zen22142.zen.co.uk/Circuits/Timing/1hr_timer.htm