Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
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Which MAX3232 IC's for simple UART to RS232 converter?
I am trying make a TTL to RS232 converter.
I have designed my PCB for 16 pin SMD sop16 and max3232 CSE+. But when I was buying from a store (store link), I saw other types of max3232. I've bought and ...
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Raw mode control of USB device via TTL
An industrial device can be connected to a host computer via a standard USB port.
The USB port on the device itself is indeed a CH340 USB-to-TTL converter, which allows to control the device through a ...
- 1,025
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BJT circuit with totem pole output
In the circuit above, I don't understand how to close and open the BJT that I circled.
To be specific, I think that when I give input 1 the circled BJT should be opened, but how? What is the voltage ...
- 11
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What does "limit of 1 TTL LS load" mean?
If I read that a line has a limit of 1 TTL LS load, does it mean that I can attach only a TTL gate? I know that other options exist, for example, the HC, however, in the case I have only LS gates, how ...
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Do stateful 74LS series chips start in a defined state?
Specifically, 74161 counters and 74377 registers, can I rely on them to be full of zeros on power on?
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What is this chip called? [closed]
I need a TTL chip 74 series, that takes in some amount of inputs and one enable bit. When the enable bit is high, the output is the same as the input. When the enable bit is low, the output is all low....
- 139
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K155ID1 power dissipation
I build my own nixie clock with four digits (IN-14, 10k anode-resistor) with a seperate K155ID1-IC for each digit (so no multiplexing). Also, I am only using the 0-9 range, so every tube has one digit ...
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ESP32-C3-WROOM: error flashing chip
I am developing an ESP32-C3-WROOM custom board, but when I tried to flash the chip using UART (FT232D USB-TTL) and Arduino IDE, I got the message "A fatal error occurred: Failed to connect to ...
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Could I have a whole batch of bad AT26C16 EEPROM chips?
I am in TTL chip heaven (India) where I can get these things for pennies on the dollar, so I bought batches of chips to tinker with. Among them a 16 AT28C16 EEPROMs, looking like new, and then 2 very ...
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To drive current with open-collector gate when input is high, do I need a buffer or an inverter?
Once upon a time I knew the answer, or could just try it. But with distance I forgot. When I use an open collector, I do it to drive some load. So High means current is flowing. But when it is used as ...
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Frequency counter schematic
I was wondering what's wrong with my Proteus schematic.
This schematic is supposed to show the frequency in Hertz on the display but instead only three zeroes are displayed.
Is there any component ...
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74xxx logic. Cheapest, most space saving way to invert 10 logic outputs
Please see this circuit.
I'm trying to design a circuit that allows you to use a single button to increment a counter from 0 to 9 (then it will loop). Diode logic will convert the 10 logic outputs to ...
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Is there a standard way of doing a TTL Hi-Z buffer?
I found many examples of IC internals for CMOS Hi-Z (tristate) buffers, but none for the TTL family.
I guess that in the TTL world, the "open collector" is much more common, but I see that ...
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Schematic Review: PIN diode switch driver
I've designed a PIN diode RF switch driver, specifically to drive HP33000 series switches. Unfortunately, these are very old, and not much documentation exists, so I'd like to ask for advice from ...
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Correcting the lower output level of a square wave generator
I have assembled a square wave generator following this schematic from an old book.
R1 and R2 are both 1 kohm, C1 is 68 pF, and C2 is 2.2 nF. The author of the book claims that this combination is ...
