You’ll need one of these tubes for each of the six digits of the time display. Conceptually, using a Nixie tube is fairly easy: You just need to design circuitry that applies power to one of the ten pins to light up that number. In actual use, it’s a little more difficult because more power is required than is generally available from the transistors in integrated circuits. Special circuits called drivers for Nixie tubes are available to supply the necessary current.The digital circuitry for a Nixie tube must convert the binary-coded decimal numbers coming from the flip-flops into separate signals for each of the ten pins. ... This circuitry is therefore called a BCD decoder:
This image shows how you'd convert the binary decimal into decimal for a nixie tube.
basically you have AND gates (the fingernail looking thing) hooked up for each decimal number. the AND gates take 4 inputs and only out puts a signal when all 4 are inputing a signal
so for the number 5 in binary 0101 to wire that up you'd have the two "0" s going into an inverter (the triangles with hats) and then into the AND gate and then of course the two "1" digits just wire straight to the AND gate. That AND gate then is wired right to the 5 pin on the tube.
for example section "a" only shuts off when the digit is 1 or 4 so you can use the circuit from the nixie clock and have a NOR gate running from digit 1 or 4 into section "a". NOR gates always output signal unless one of their inputs is on.
talking about dot matrix displays. a typical one consists of 35 leds arranged in 5 columns and 7 rows. Instead of wiring up all 35 they are activated one column and row at a time but in really quick succession so the eye thinks they are all on simultaneously. (7 +5 makes 12 connections instead of 35).
All the numbers are encoded via regular diodes and then a very fast counter is used to cycle through each column really fast.
I'd say look at the bottom of books website to get the idea
basically your leds (represented by the triangles with arrows) are wired up like this. and since leds are diodes (meaning electricity passes through in one direction only) you can be sure that only the ones that voltage are supplied to will light. and then to select a particular column you just have to supply a ground at the right moment to that column. (if you follow the voltage to ground you can see that only those particular leds can light up)
Apparently the circuit is slightly more involved but you reduce the connections if you store 1 bit of memory at 8 different instances of time rather than storing an entire byte all at once.
if it ain't obvious you chain 8 of those circuits together to store 8 bits. In the case of storing 8 bits at once you'd chain all of the write inputs together and then you'd have 8 separate bits going in and 8 bits going out (8+8+1 is 17 connections)
in the case of storing 1 bit at eight different times you need an 3x8 selector to choose which of the 8 circuits is being written to. The writes and the data are all chained together. and then 1 bit output. so 1 write + 1 input + 3 for your 3x8 selector + 1 output is 6 connections.
Not all memory is random-access memory! In the late 1940s, before it became feasible to build memory from vacuum tubes and before the transistor was invented, other forms of memory were used. One odd technology used long tubes of mercury to store bits of information. Pulses at one end of the tube propagated to the other end like waves in a pond, but these pulses had to be read sequentially rather than randomly. Other types of delay-line memory were used up into the 1960s.
wanted to look into the mercury memory thing a bit. Got this paragraph from wikipedia
Mercury was used because its acoustic impedance is close to that of the piezoelectric quartz crystals; this minimized the energy loss and the echoes when the signal was transmitted from crystal to medium and back again. The high speed of sound in mercury (1450 m/s) meant that the time needed to wait for a pulse to arrive at the receiving end was less than it would have been with a slower medium, such as air (343.2 m/s), but it also meant that the total number of pulses that could be stored in any reasonably sized column of mercury was limited. Other technical drawbacks of mercury included its weight, its cost, and its toxicity. Moreover, to get the acoustic impedances to match as closely as possible, the mercury had to be kept at a constant temperature. The system heated the mercury to a uniform above-room temperature setting of 40 °C (104 °F), which made servicing the tubes hot and uncomfortable work. (Alan Turing proposed the use of gin as an ultrasonic delay medium, claiming that it had the necessary acoustic properties.[5])
talking about tri-state buffers. Which are just transistors but what it allows you to do is make it so you can run multiple outputs together without risking a short circuit.
Because the three states are basically off, on, and high-impedence. That third state is almost like the input has been detached completely from the circuit (a circuit in an off state still has some voltage which is one reason why chaining multiple outputs together causes problem)
important in the instance of memory because without the use of transistors you'd need this ridiculous 16 input (in the case of 16x8 memory) or gate repeated for every single bit.
ok so when we talk of a 32bit system (if I'm understanding correctly) the 32 bits refers to the length of the address used in accessing your ram.
So like when we stored just 8 bits we could do bytes instead and if we stored 8 bytes we would also use a 3 digit (3 bit) address to look up any of the particular 8 bytes that was stored. (111 in binary is 7 so 8 bytes since we count starting at 0) put another way this would be 2 to the power of our address length so 23 bytes
so in a 32 bit system your ram is limited to 232 (in case markdown is being mean this is 2 to the power of 32) bytes which is 4,294,967,296 bytes or 4 Gigs
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