![]() ![]() I suppose I shouldn’t be so because as I said the 7 seg still functions and I still have a functioning Vreg section of the circuit. I have more 4511’s but I’m nervous about installing any of them. The display is still functional so I didn’t burn out any LED segments but now I get NO lit LEDs at all. Anyhow, once I realized I had made that mistake, I used the 5v side of the regulator to retest the display and very shortly I had no display at all. I got a bright partial display that made on sensible numerical figure. I used resistors to limit current to the LED which is a 1 inch 7 segment. I only activated the inputs at pins 1,2,6 and 7 one at a time and made the mistake of applying the full 12v which is supplying the circuit which I used a 5v reg to power the IC. I finished the display circuit and was attempting to test it. The trans is controlled by a TCU which I assembled from a kit. Ok so I assemble a circuit similar to this one for which it was supposed to display only the digits 1 -4 to indicate which gear an automatic transmission is in. 74HC46/47/48/49: BCD to 7-segment decoderĭownload the PDF datasheet for the IC 4511 here:.4026: Decade counter with 7-segment display outputs.Or try one of the following 7-segment decoder alternatives: But the functionality and the pins are the same.Ĭan’t find any of these in your local electronics store? Then check out my list of online stores where you can find components and tools for all your electronics projects. This has to do with the manufacturer of the chip and the technology used. Usually with a few extra characters at the end (Ex: CD4511BE). Later, you can modify the input of this circuit to instead be the output of a counter that counts seconds, to create a stopwatch. This is a fun circuit to build as your first 7-segment display circuit. Four resistors (R8-R11) of 10kΩ resistors.A 7-segment display (Must be common cathode.The CD4511 controls the 7-segment display so that it turns on the correct segments for displaying the number. Set this pin LOW for normal operation.īelow is an example circuit where you set the input number using switches. When HIGH, the last data is displayed regardless of the changes to the BCD inputs. The LE (Latch Enable) pin, also called store, is used to store the current value. You can use it to control the brightness of the display with pulse-width modulation (PWM). The BL (Blanking Test) pin turns off all segments when LOW. The LT (Lamp Test) pin is there to test that all the segments of the display work. Pins a to g are the output pins that you connect to your 7-segment display. Pins D0, D1, D2, D3 are the BCD inputs through which you feed the number you want to show on the display in binary format. ![]() Check the datasheet of your version of the chip for exact values. Although, some versions of the 4511 chip support up to 20V. You can use a power supply voltage between 3V and 15V. To be able to use the BCD to 7-segment decoder in the chip, you need to first connect the VDD pin to the positive supply terminal and the GND pin to the negative supply terminal. The logic gates below convert the bits from the latches into 7-segment output. But when LE goes HIGH, the last data present on D0 to D3 is stored in the latches and the segment outputs stay unchanged. This means that when LE is LOW, the segment outputs ( a to g) are determined by the data on D0 to D3. ![]() But when EN goes low, the last input value is stored onto the output Q and cannot change. When the EN input of a D latch is HIGH, whatever is on the D input is transferred to the Q output. So, how exactly does this IC convert binary codes to decimal numbers? It does so by using a combination of logic gates and D flip-flops.įrom the HEX4511B datasheet, we can find the internal circuit of the 4511:įor each input bit (D0-D3), there is a D latch. ![]()
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