Aug 12, 2014 · Also to funct5ion as a clock the 7490 (decade counter) needs a clock pulse provided by a 555 timer and the 7447 needs its Lamp-Test (LT) & Blanking Input (BI) set to V-Supply (High or 5V for a 7447) and the Latch Enable (LE) input set to 0V or GND. Here is a schematic from Forrest Mims Engineer's Notebook (LLH-Publishing, 1992) P.59:

Jun 25, 2014 · To get the collector current we have to know the base current, which is (sunk into the 7447) (5 - Veb - Vec)/R3 -> (4.3 - Vec)/R3. But the fact that Vec is a function of the operating point and R1 is present, I tend to not get these correct. \$\endgroup\$ –

You have your 7447 and 7490 mixed up. The 7490 is the decade counter. The 7447 is a "BCD-TO-SEVEN-SEGMENT DECODER/DRIVER". Here is the datasheet for 7447. If you look on page 3 you will see a diagram of the segment outputs for binary inputs above 9.

Jun 27, 2023 · I have designed a circuit to display the 2-digits data using two 7447 decoder. The design is shown below. I have two outputs, O1 and O2. O1 represents the ones digit while O2 represents the tenths digit. However, when I simulate the waveform, it is not correct partially. For example, '63', the '6' seems like is not a correct output.

May 19, 2022 · We used one 74LS47 IC in our lab, which we connected to a 7-segment display and tested the outputs. Now our instructor has told us to cascade two 7447 ICs together and implement it on a 7-segment display. Also, the instructor did not show us how to cascade 2 ICs together in general. So I apologize if my question sounds a bit silly.

Jan 6, 2025 · I’m using the 7447 BCD to 7-segment decoder IC with a common anode 7-segment display, and I’ve noticed something odd with how it shows the numbers 6 and 9: For 6, it lights up segments f, e, d, c, g, but skips a, so it doesn’t look quite right. For 9, it lights up segments g, f, a, b, c, but skips d, which also makes it look incomplete.

Jun 19, 2014 · What is the practical difference between a 7446 ("BCD to 7 segment decoder/driver with 30V open collector outputs"), a 7447 ("BCD to 7-segment decoder/driver with 15V open collector outputs"), a 7448 ("BCD to 7-segment decoder/driver with Internal Pullups"), and a 7449 ("BCD to 7-segment decoder/driver with open collector outputs").

Oct 3, 2020 · The TTL Databook suggsts the only key difference is the voltage rating of the output transistors. 7446 : 30V, 7447 : 15V. Unless you're driving Nixie tubes this probably doesn't matter. \$\endgroup\$ –

Dec 17, 2022 · The 7447 internal transistor adds a few hundred millivolts to this, leaving perhaps 2.8V for each series resistor to soak-up. If you decide that 5mA LED current provides a bright-enough display, then each of seven series resistors would be 2.8V/5mA = 560 ohms. Some LEDs are super-bright while others (perhaps older) are not.

Jan 24, 2025 · The 7447 has a feature called "Ripple Blanking" (RB). By connecting the RBO (Output) of the most significant digit to the RBI (Input) of the next digit leading zeros will be suppressed. Since you generally want to display 0 for a 000 reading the least significant digit's RBI should be connected to +5V.