2 byte full adder

This handy thing is only a full adder. It can’t subtract or anything else. On the left side, there are the first 16 bit inputs, the second 16 bit inputs are on the back side. (Unfortunately not visible) The right pins are the 17 bit output. (16 bit with a carry out / overflow) The two loose wires are for […]

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2 byte sram

This project is an upgrade from the 16 bit SRAM module. The requirements were: Easy stackable If possible, less SMD components Small as possible If a bug occurs, it must be easy to find and desolder No need of some extra drivers (Only a level decoder is necessary) As little current consumption as possible General information:   RS NAND Flipflop […]

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4 bit decoder

This decoder is used to address the 16 byte RAM. A typical decoder has n input pins, an enable pin and 2n output pins. In the picture you can see the 16 output pins, the 2 supply voltage pins, then comes the enable pin (Vcc = ON), at last the 4 inputs. (Until 2017, I made all my circuit boards […]

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16 byte ram

In the picture above, you can see the rows of the memory array. Each of it has 1 byte. A noteworthy thing is that this ram-design uses the fewest amount of npn transistors (BC847). Every cell has a word line, two write lines, one read line and the two power pins. The big board on the bottom, connects all write […]

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1 byte ram

One of my first prototypes of a 1 Byte SRAM. It has 8 input pins on the left side and 8 output pins in the middle. The next 2 pins are for the commands (Read/Write). On the right side, there are the power pins. Each cell uses 6 transistors and it has an on-board driver. This is a part of […]

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8 bit computer [Advanced adder]

This is my 2nd try of a full adder. It is made out of 600 SMD components, parts got silver plated and consumes about 2 A. It handles negative / positive numbers and can add or subtract them. 274 SMD NPN transistors, SMD resistors (10kΩ and 1kΩ) and 0 Ohm bridges are only a small insight into this huge project. […]

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First, second try of a 8 bit addder

  The big modules in the middle are the full-adders, on the right are the half-adders and on the left side the XOR-gates. (XOR and the half-adders are needed to do the hardware implementation of subtraction)   This was my first build and it ended up with some critical design faults. It took me about half a year, to find […]

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