Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
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Why am I seeing -5 V or lower on the output pins reading an Intel 1702A EPROM?
I am building a breadboard/Arduino reader to dump the data on a very old Intel 1702A EPROM chip. (data sheet) When doing some basic testing by tying all the address pins to ground, I am seeing ...
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How can I avoid a clock glitch?
I have a clock with a 50% duty cycle, driving a 3-bit ripple counter.
When Q2 is high, external lines such as address are stable. I want to generate a short read pulse between 50% and 75% of the Q2 ...
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pull-ups between logic gates
I'm trying to understand why, on this circuit bit, they used pull-ups resistors between logic ICs of the 74LS and CD4000 families. Specifically I'm talking about resistor array RM1 and R1. All the ICs ...
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Which logic gate family is used in a PC? TTL or CMOS?
I read that the propagation delay of CMOS logic gate is longer than TTL; therefore they are not used where speed of processing is important. I thought computers or computer cpu is using CMOS. ...
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Switching relay with a PNP and TTL levels
I can not wrap my head around the fact how I can drive a relay (24V, 160ohm) with an tip32a PNP transistor which has TTL inputs from a controller.
I can easily calculate my resistors when I use the ...
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Bi-colour LED resistor value
I am trying to calculate a suitable resistor to give about 2mA to the a bi-colour LED in the following configuration:
simulate this circuit – Schematic created using CircuitLab
The LED package ...
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TTL NAND gate analysis
I was looking into Millman's Microelectronics book, 2nd edition, pp. 245 - TTL NAND Gate.
I am a beginner in electronics and was looking into this book just because of an assignment problem about a ...
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CMOS (or CMOS compatible) shift register with latched open-drain outputs
I've been looking for a 3.3V compatible shift register (SIPO) with latched open-drain outputs. I've settled on a 74xx596 (not a '595!), but of all the 74xx CMOS series I've been looking at omit this ...
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TTL NOR Gate analysis
I'm looking at the design below. I am reading this webpage where the picture came from.
What I'm aiming at is the wisdom behind the design. Looking at the two transistors facing downward, I assume ...
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Driving LEDs / other small loads with a 74HC06 or similar inverter
I was recently reverse-engineering some firmware (and other bits) from a router, and spotted that the front panel LEDs were driven from a 74HC06 hex inverter gate chip rather than a proper LED driver.
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how to interface HCPL-3700 optocoupler to an input pin of ATmega16L
I want to detect logic of the mains supply (230VAC, 50Hz) and feed the output of HCPL-3700 into ATmega16L. I read through the datasheet but could not understand how to calculate the resistor values. ...
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Dual power supply confusing TTL serial?
Sorry for the vague title: I'm a bit of a noob at analogue electronics, more a logic &software guy. Basic problem is I'm sitting at the end of a cable with a USB powered Arduino trying to send ...
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How to detect Serial or TTL signal for a PIC?
I have a Microchip PIC with UART support. If i understand correctly, the UART is able to natively handle the TTL serial signal.
I'm expecting input signal that should be TTL (0/5V), but it could be ...
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7405 TTL Chip outputting nothing when given low input
I’m struggling learning how to use some of these components for a lab. One thing I noticed is that when giving the 7405 hex inverter a low input, the output when checked by my logic probe shows there’...
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What is the fastest 7400 series family? Is 74VHC faster than 74AHC?
What is the fastest 7400 series logic family?
Is 74VHC* faster than 74AHC*?
This list does not seem to be in any particular order:
http://en.wikipedia.org/wiki/7400_series
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