Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
588 questions
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3
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Is 74LS00 max current a capability or a limit?
a newbie question here.
Many datasheets specify the max input/output current for the integrated circuits. I'd like to know if that is the maximum they can provide or the maximum above which they break....
- 163
2
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2
answers
209
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Trouble connecting RS485 turbidity sensor to a Raspberry Pi
I am trying to connect a Turbidity sensor that operates using Modbus to a Raspberry Pi. The sensor is an industrial-grade device and comes with the needed communication protocols (http://www.sonbus....
- 113
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4
answers
104
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Why would you put a pullup resistor on the output of a TTL compatible IC?
I am building a square wave generator with a ne555. The datasheet in section 6.3.2 Astable Operations has an example circuit that is essentially the same as my practice circuit but with a 1k pullup ...
- 21
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0
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41
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ESP32 WROVER to control iRoomba 650 via Mini-DIN using Open Interface and JavaScript
I found the WesBos video on how to control an iRoomba using an ESP32 and I am having an issue where the commands from the ESP32 are not executed. Here is what I’ve tried.
confirmed pin locations and ...
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3
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1
answer
192
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7400 vs 4000 series pinout difference for quad two-input gates; explanation?
All of the quad two-input logic gates (AND, OR, NAND, NOR, XOR) have consistent pinouts within the 74xx family [Edit, turns out not true], and a different consistent pinout within the 40xx family [...
- 2,861
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0
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95
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Should I use plain registers or synchronous counters for a 16‑bit TTL design with load, clear & increment?
I’m designing a fully hard‑wired TTL module (no HDL) that must provide:
Parallel load (active‑high LOAD)(Synchronous)
Asynchronous clear (active‑high CLR)
Synchronous increment (active‑high INC)
...
- 101
1
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1
answer
142
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Problems with SIM808
I have a SIM808 Shield from DFrobot which works fine, I can use it with my Arduino Uno or with my USB-Uart Modul and communicate with it without any problems. However, when using another SIM808 from &...
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0
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Equivalent to a 74LS295 shift register? [closed]
I'm redesigning an old Soviet ZX Spectrum clone circuit so it can be assembled with modern components.
However, I've been having some trouble looking for an equivalent to the obsolete 74LS295 (a ...
- 41
2
votes
1
answer
115
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24-bit parallel image signal length matching requirements
We are using output of deserializer MAX9280 for display. The resolution is 800x480 with frame rate of 60hz. PCLK is around 25Mhz. We thought length matching is not important in this application, so ...
- 41
2
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1
answer
164
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74181 A=B behaves differently in Logisim Evolution
I wanted to rebuild a 74181 myself in Logisim Evolution, first I tried the prefabricated ic there and wired it up successfully and it worked as expected.
Now I wanted to use the template from
to ...
- 23
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1
answer
105
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Converting RS485 to TTL and then to LIN
Is it possible to convert an RS485 signal to TTL and then to LIN without using microcontroller?
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0
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SSR based control of window blind motor with protection
I have a pair of separate SSRs based on the G3MB 202P. Both are controlled by 5V logic from the MCU. Pin 2 of connectors J1 and J3 are fixed to 5V. The Input0 and Input1 are directly attached to the ...
- 191
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3
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383
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Driving a 74LS gate with a 4000-series output
I'm making a PCB based on a schematic I found online. On the schematic, a diode AND gate takes in signals from a 74LS298 multiplexer and a 4520 binary counter and outputs to a 74LS86.
Since I've added ...
- 41
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4
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263
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Which is more feasible/makes more sense to implement at the discrete transistor level, NMOS logic or TTL?
I'm currently working on a discrete transistor computer project, and I'm somewhat caught between TTL and NMOS. I was originally going to implement CMOS logic, but after I made a previous post, someone ...
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2
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DIP or DIP like auto-bidirectional multi-voltage level translator [closed]
I am looking for an auto-bidirectional multi-voltage level translator for converting TTL and LVCMOS level signals.
I understand that the 3.3 signal coming from the LVCMOS system is safe for the TTL ...
