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Nixie Clock Version 3
Then the DRL output goes high so the capacitor starts to charge up. I personally prefer hour mode. I had to use a very small 8-volt transformer that just barely fits inside the case xatasheet supply the low voltage power. This current draw will pull up the dataseet input of the 74LS to a logic 1 momentarily. Most chips come with four AND gates in one, or 6 inverters in one. Recall that the 74LSs trigger on a falling edge, not a rising edge.
I originally planned on using a Mostek MK 6-digit clock chip that multiplexes the digits. When the capacitor stops charging up, the 22K pull-down resistor pulls the clock input down to fatasheet logic 0.
It took some experimentation before I could get the signals to work correctly between the chips.
Even a seconds display can be added to this circuit, simply add two more decoder chips on U3b and U4a. After discovering this noise problem, I swapped them around. After overcoming the noise problem with the 74LSs in the clock, I learned of another minor design issue.
The reason is datsheet if segment F is off or segment G is on inverter produces a logic 0then the diode s will pull down the output to ground and produce a logic 0. This falling edge triggers the 74LS to advance one more time.
I figured that with the in the front, it would buffer out more of the noise and generate a cleaner clock pulse for the 74LS chips. The fundamentals of my binary clock circuitry was based on Hans Summer’s binary clock, but his operates in hour mode. I found a “trait” of the 7-segment zero digit, segment F has to be on and segment G has to be off.
I came to a point where I thought I had gotten the design, so I proceed to build the clock.
Motorola – datasheet pdf
For the ten hours, I didn’t want datssheet waste another 74LS and chip just to display zero and one. I built a case out of cedar, and the amount of space I had inside the case was rather limited so I was unable to pursue my idea of using neon bulbs or LEDs for displaying the binary time directly from the 74LS counters.
Without the K resistor and 0.
I tossed this idea out and decided to drive the nixies directly, using BCD-to-7segment decoder chips. I designed the clock circuitury hoping to achieve a perfect design that uses all of the logic available in all of the chips I would need. The “C” that is switched on to make a zero comes on when the clock is in the single digit hours. I figure since the latter was normally used in older computer systems, the power supply and input signals are expected to be well-filtered and free of noise.
I used the for the first stage to divide 60Hz to 10Hz. As you can see in the schematic, the portion marked in blue uses two AND gates and one inverter gate. A colon indicator can be added by using the 1Hz pulse off pin 5 of U3a.
Therefore, both diodes have to have a logic 1 in order to allow the output to rise to a logic 1. I realized a design flaw when I finished the clock.
However, after trying the chip out with two nixies, I found that the brightness was not very strong. In the process of constructing the clock, I found that these chips were extremely sensitive to noise. So much for the “perfect” design that used all of the chips wisely. I planned on placing the neon bulbs under each digit, so if you’re plain then look at the Bs and if you’re a geek then look at the binary below. However, I had to delay the pulse from the DRL until the 10 minutes counter finished sending its clock pulse to the 1 hours counter.
Below is the pinout of the B nixie: However, that didn’t work out due to complications with the circuitury and the amount of room in the clock case I made. None of the other digits have this trait. The two diode AND gate, one connected to segment F and one to the inverted segment G, will produce a logic 1 only when segment F is on and segment G is off. These versatile nixie tubes can allow for a variety of characters and digits with different styles. The pulse goes high then low, and the falling edge triggers the 74LS I think if the 74LS operated on a rising edge, the circuit might work without the capacitor and resistor.
The other segments for the zero are all wired together and switched on and off by a flip-flop. One advantage to use what is essentially a binary clock with 7-segment decoders is to have small neon bulbs or LEDs driven directly from the BCD outputs.
Assembly and Testing Completed view of assembly bottom view Back to Top. Click here for the schematic diagram of the four B nixie clock. I also found out that the circuitry draws a good amount of current so I couldn’t simply obtain low voltage from the voltage doubler datashedt regulate it for the low voltage supply like I could in my first two nixie clocks.