Data sheet acquired from Harris Semiconductor. SCHSC − Revised October HCDB consists of an oscillator section and December CDBMS. CMOS 14 Stage Ripple-Carry Binary Counter/ Divider and Oscillator. DATASHEET. Pinout. Functional Diagram. HEF Datasheet, HEF PDF, HEF Data sheet, HEF manual, HEF pdf, HEF, datenblatt, Electronics HEF, alldatasheet, free.

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Axeman 3, 14 These kind of capacitors usually have a black line on top of their body. I have covered the time base and the counters here. The oscillator part is built as described in the HEF data sheet. This signal is fed to the seconds counter, as described below. Otherwise the roll over of the minutes counter would advance the hours counter too.

My way of keeping this site alive. Another link from an Illinois ECE college course states:. When the hours counter is reset, so is the flip-flop, making its Q ddatasheet high. We need 1Hz, not 2Hz, to feed to our seconds counter.

This helps to tune the frequency of the time base to the correct value. So, the logic and Master Reset is working, but the counter is not. Let’s start simple, the buttons, hwf4060 are used to set the time. When the carry pulse goes high too, the output dayasheet IC9B goes low briefly.

The output pulse from IC10A also goes out to the minutes counter, which has to be advanced at every overflow of the seconds counter.


The other sheet covers the display circuit and the power supply. The relative high contact resistance can already be a problem for DC and very low frequency circuits. My way of keeping this site alive.

It also produces several other division ratios. It doesn’t dataseet matter whether we use a rising her4060 falling edge here because this carry pulse is very short.

We haven’t talked about the carry from the seconds counter hef400 the minutes counter yet. BPete This could be a problem with the original datashert crystal Unfortunately I don’t have the datasheetbut the 11MHz one that I used, with 22pF capacitors, is the one that I used in dozens of other circuits, without problems.

The CLK input to the flip-flop is low, because the hours counter has just been reset to 0. In SET mode the SET signal is high, and the seconds to minutes carry can never occur because the seconds counter is held in reset. This page will describe sheet one in detail, while the next page will describe sheet number two. The clock can be in one of two different modes, in Run mode or in Set mode.

The precision of the resistor value has no effect on the precision of the time base B. The 14 stage counter is receiving a signal from the oscillator stage as I can see it on the pin 9 but doesn’t count. You could even remove the oscillator and just toggle RS manually or use a function generator. Navigation How to navigate Sponsors Please consider clicking on the Support Me button to show your appreciation.


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This pulse is very short because its cause is removed by the reset almost instantly. The Wikipedia Page on them states pF per contact pointso you may have far too much capacitance on your crystal.: It also produces several other division ratios.

I would make sure the capactor values C6 and C7 are within the range reccomended in the crystal data sheet. The Minutes Counter Next stop, the minutes counter. The problem could be related to testing at near the device’s maximum frequency on a breadboard.

In my case the pulse was about ns wide. Please consider clicking on the Support Me button to show your appreciation. And now the hours counter. The precision of the resistor value has no effect on the precision of the time base B. Both inputs of IC10D are high when the button is pressed, making its output low.

This allows you to accurately synchronize the clock with a known good time source. It’ll give stiffness on ‘s supply lines and will give extra capacity to the to drive various parasitic capacitance on its outputs. However, it would make changing the crystal somewhat more involved.