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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But this time the maximum count value is limited to Otherwise the roll over of the minutes counter would advance datashfet hours counter datashert. IC4B tries to do the same for the 0. While the clock is in SET mode there won’t come any carry pulses from the minutes counter and that signal is constantly high. Hef0460 clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand dagasheet your continued use of the website is subject to these policies.

Post as a guest Name. I’m building on a breadboard a 16Mhz oscillator part of another circuit with the HEFB using an external xtal.

This is a nice 0. I tried with some random values, from 1 to pF, and nothing. When the carry pulse goes high too, the output dayasheet IC9B goes low briefly.

Once the counters reach that state they are reset back hef40660 0 again. TP1 is a test point at hef datasheet you hef datasheet measure the buffered hef datasheet While the clock is in run mode SET is high, opening the gate for the carry pulse. Pins are almost always zero. The Buttons Let’s start simple, the buttons, which are used to set the time. The Hardware Part 1 You can download the circuit diagram dataaheet.


The output pulse from IC10A also goes out to the minutes counter, which has to be advanced at every overflow of the seconds counter. It is spread over two sheets, one sheet covers the time base and the seconds, minutes and hours counters. I suggest fitting a 10nF to nF ceramic capacitor next to the hole of pin datasheef and pin 8 respectively. If you can, I would strongly suggest lifting the two crystal pins bend the leads on the DIP package up, so they poke out of the device datasbeetand soldering the crystal and caps directly to them.

HEF Datasheet, PDF – Alldatasheet

The Minutes Counter Next stop, the minutes counter. Let’s start simple, the buttons, which are used datashet set the time. Sign up using Email and Password. The Q output will be used by the display part of the circuit to suppress the leading 0 of the hours counter.

It is very important to use 0 tempco capacitor for C4. The clock can be in one of two different modes, in Run mode or in Set mode.

As a matter of fact, there’s no more on sheet number one to be explained. When the carry pulse goes high too, the output of IC9B goes low briefly. On the next page I’ll explain datsheet display circuit and power supply of the clock. These kind of capacitors usually have a black line on top of their body.

You can download the circuit diagram here. It must be a problem so silly that’s too evident for me to see!! You can download the circuit diagram here. When the clock is switched to SET mode though, the SET line goes low, which keeps the reset line to the seconds counter constantly high, preventing the seconds counter to count. This page will describe sheet one in detail, while the next page will hef406 sheet number two. However, it would make changing hef4006 crystal somewhat more involved.



This allows you to accurately synchronize the clock with a known good time source. From then on the flip-flop remains in that state, until the hours counter is reset to 0 again. One significant factor that most people neglect is the series parasitic inductance on the supply line.

What is IC3B doing there? Solderless breadboards are further limited by their voltage and current ratings. The other sheet covers the display circuit and the power supply.

Eventually datasyeet output of IC10C goes high when a button is pressed. Together with this knowledge you should be able to build the clock yourself too.

This removes the breadboard from the connection entirely, and will likely be far more reliable.

oscillator – HEFB counter doesn’t count – Electrical Engineering Stack Exchange

We need 1Hz, not 2Hz, to feed to our seconds counter. Its signal level is constantly low, with only a very short rising pulse when the counter reaches 60 minutes.

This is negligible for most frequencies, but if you are operating in the RF spectrum this quickly becomes problematic.