Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
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PCB and trace design for high-speed TTL
I am designing high-speed TTL-based processor.
I will be using only fast AC, ACT and LVC series, so switching frequencies will be in 100Mhz range with 1-3ns fronts.
I plan to use homemade 2-sided ...
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Why does the TTL NAND gate use a 4 transistor design instead of 2?
Why does the TTL NAND gate use 4 BJTs to make the gate when it could be done using only 2?
I assume that the design with the 4 transistors amplifies the current so multiple levels of gates can be ...
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Which logic families interpret a floating input as a definite value?
From what I remember, from decades ago, 1980's 5v TTL chips would see a floating input as a zero (because they switched on current, rather than voltage). Update: it seems they were interpreted as ...
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True 5V CPLD other than PIC/Altera ATF150*?
Are there any True 5V CPLD's families still in manufacturing other than PIC/Atmel ATF150*?
I am talking not just "5V tolerant IO", but rather ones with 5V VCCIO, able to drive 5V loads without ...
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How to convert sine wave from an oscillator to TTL signal for microcontroller?
I tried to measure inductance by using a colpitts oscillator to generate sine wave. It works. I need to convert the sine wave to 5V square wave to feed to a microprocessor. The sine wave is coupled ...
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IC chips and datasheets
I'm still just beginning my adventure into electronics and IC chips and datasheets have me confused so I'm going to ask a series of beginner questions will help me and hopefully others as well.
There ...
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TTL NAND gate (totem pole) current and voltage analysis
I am working on a few practice problems for my course and I am unsure about my working throughout.
hoping for some feedback and guidance from the community as it's not my strongest topic.
Here is ...
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Is hardware flow control necessary?
I want to communicate using a serial cable to a device that uses RTS/CTS flow control and 115200 baud speed. I want to use this Sparkfun TTL to rs232 adapter, but it has no RTS or CTS pins. What can I ...
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Why do some Arduino-compatible boards provide a crystal for the CH340? [closed]
I have an uno-shaped Arduino compatible which uses the CH340(G) serial to ttl converter chip and it is connected to an external crystal.
I also have nano shaped compatible which uses the CH340(C) ...
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7805 5v Regulator outputting 5.8v? TTL chip not functioning correctly? LED + TTL chips?
I've read a number of other similar questions to mine, but none of the answers have helped me so far. I also don't have any electrical schematic software, so I'm afraid I'll have to explain in words ...
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Tachometer IC that does not require zero-crossings?
I recently built the basic tachometer circuit in this LM2917/LM2907 Datasheet shown below using the 8-Pin version of the device. I realize this circuit requires a VR pickup sensor, and so the LM2907/...
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What is the use of transistor in the input side in TTL logic family?
Second transistor will turn ON and OFF if input voltage is directly connected to its base terminal. Then why a coupling transistor is used at the input side of a TTL logic gate?
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What is this chip enable circuit doing? (old TTL, with diode, with pull-up?)
I'm trying to understand a small portion of a (vintage, TTL) circuit design and I'm a little unsure of what's going on in this section*, which determines whether the Chip Enable signal on a particular ...
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Buffering long TTL lines
I'm laying out a stacked PCB where I have 3 or 4 boards stacked on top of each other with signals propogating down with female/male headers (think Arduino shields). Shared control signals are ...
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Converting the 400 picosecond pulse train to 15 MHz clock signal
My goal: I am trying to phase lock a 74HC-based digital circuit from a clock reference at 10~15MHz pulse repetition rate. The pulse width is around 400 picosecond. The peak voltage is sometimes below ...
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