Mar 30, 4. This procedure is repeated on all except the LSD, which does not require zero suppression. Apr 5, 18, 3, If cascaded B ICs are required to give automatic leading-zero suppression, the basic Figure 17 circuit must be modified as shown in Figure 18 to provide ripple-blanking operation. Interfaces for Computer-Controlled Test Systems A short introduction to some of the more popular interfaces used to connect test instruments to computers. I’ve connected a to a common cathode seven segment display. Hello, With the you do not need resistors for the leds.

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Posted by B-Sparkes in forum: Enabling the display can be connected directly to the outputs of the IC without the use of external current-limiting resistors.

The segment output currents are internally limited to about 5mA at 10V or 10mA at 15V. Mar 30, 6.

In this method, the microcontroller would send BCD binary coded decimal on 4 output pins to the chips. Shown above, is an example application of the 74LS48 7-seg decoder circuit. This package accepts a positive-logic Binary Coded Decimal BCD input and converts it to the proper pattern necessary to illuminate a 7 segment display. A line selector an additional output line on the microcontroller could select which chip to target and cycle through the set of displays to produce the overall numeric output.


The B can be used to drive most popular types of seven-segment displays. The B is very easy to use, and has only three input control terminals; of these, the not-LT pin 3 pin is normally tied high, but turns on all seven segments of the display when pulled low.

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Need dsplay brush up on your electronics principles? Method of modifying the Figure 17 circuit to give automatic leading-zero suppression. When the not-LATCH terminal is pulled low, the BCD input signals that are present at the moment of transition are latched into memory and fed in decoded form to the seven-segment outputs until the not-LATCH pin returns to the high state.

7448 BCD to seven segment display

Driving a fluorescent readout with a B. A PWM pulse-width modulated signal can be applied to this pin to provided varying brightnesses to the LED display being driven, allowing user control of LED dimming for applications such as power saving by decreasing the brightness during times of low ambient light. Do you already have an account? Mar 30, 1.

Using Seven-Segment Displays — Part 2

Using switches for the input data. BCD to seven segment common anode display Posted by cdennis in forum: What am I doing wrong any help would be greatly appreciated Thanks. The rest of this article describes a few of the most popular of these devices. The 74LS47 has active-low outputs designed for cisplay a common-anode LED display via external current-limiting resistors Rxas shown in Figure 2.


Figure 1 shows the functional diagrams and pin designations of these devices, each of which is housed in a pin DIL package. Driving a gas discharge readout with a B.

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Mar 30, 2. Mar 30, 4. A special two-part feature on how to use seven-segment alphanumeric displays. Finally, the LE latch enable terminal pin 5 enables the IC to give either direct or latched decoding operation. Mar 31, RBI pin turns off all output if the BCD value is 7-degment all low used if the segment is a leading zero for hours, you don’t want Hello, Can you provide a schematic how you connected everything? The IC does not incorporate a data latch and has no facility for ripple blanking.

Way of using the B to drive a common-cathode or b common-anode seven-segment LED displays. 7448 outputs are open-collector but have internal 2K cbd pull-up resistors and have a maximum low-level output sink current of 6 milliamperes 6mA.

The display can be blanked at any time by driving the BL terminal to the logic-1 level.