Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
Any suggestions?
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
On 2018-10-16, James Harris <james.harris.1@gmail.com> wrote:
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
They can only claim 100mA as that's all that USB guarantees without
some sort of complicated negotiation. in actual use It can probably do
500mA or more (not that soldeless breadboard is suited to currents
above about 200mA)
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
USB-shaped "phone chargers" that produce 5V at 500mA or more are
easily had.
On 10/16/18 9:04 AM, James Harris wrote:
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
Any suggestions?
Sure, that'll work. But why on earth use TTL in 2018?
Sure, that'll work. But why on earth use TTL in 2018?
TTL, 0.1" through-mounts, and and bipolar transistors are all I know. I
told you I hadn't done this for years! What would you recommend 'these
days'?
On 16/10/2018 19:37, Phil Hobbs wrote:
On 10/16/18 9:04 AM, James Harris wrote:
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
Any suggestions?
Sure, that'll work. But why on earth use TTL in 2018?
TTL, 0.1" through-mounts, and and bipolar transistors are all I know. I
told you I hadn't done this for years! What would you recommend 'these
days'?
On 10/17/18 9:27 AM, James Harris wrote:
On 16/10/2018 19:37, Phil Hobbs wrote:
Sure, that'll work.? But why on earth use TTL in 2018?
TTL, 0.1" through-mounts, and and bipolar transistors are all I know. I
told you I hadn't done this for years! What would you recommend 'these
days'?
HC for slowish stuff. TTL is vaguely similar but sucks power.
On 16/10/2018 20:21, Jasen Betts wrote:
On 2018-10-16, James Harris <james.harris.1@gmail.com> wrote:
Having not touched any of this kind of stuff for years I'm looking to
power a small TTL test circuit which I intend to built on a breadboard.
I wondered if I could run it off USB power. In other words, is it
feasible to power a TTL cct via a USB lead and USB socket?
I found a "USB Mini B Breakout Board"
http://www.hobbytronics.co.uk/cables-connectors/usb-connectors/usb-minib-breakout
but I'm not sure that the PCB bit of it is necessary and, besides, it's
only rated for 100mA (which may be enough but I can't be sure at this
stage). If not USB, I guess I should go for a wall wart and a 7805.
They can only claim 100mA as that's all that USB guarantees without
some sort of complicated negotiation. in actual use It can probably do
500mA or more (not that soldeless breadboard is suited to currents
above about 200mA)
So the question is whether there's a good way to power a circuit via
USB, or whether you think I should go down the wall-wart or some other
route.
USB-shaped "phone chargers" that produce 5V at 500mA or more are
easily had.
I've been trying to work out USB power negotiation without much success.
I recognise that an un-negotiated port can draw 100mA and I know that a device can negotiate for more. I am not clear, though, on whether
there's a cable or a particular outlet which will allow higher current
to an endpoint which doesn't do negotiation.
In sci.electronics.components Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 10/17/18 9:27 AM, James Harris wrote:
On 16/10/2018 19:37, Phil Hobbs wrote:
Sure, that'll work.? But why on earth use TTL in 2018?
TTL, 0.1" through-mounts, and and bipolar transistors are all I know. I
told you I hadn't done this for years! What would you recommend 'these
days'?
HC for slowish stuff. TTL is vaguely similar but sucks power.
It seems to me that hardly matters unless you plan to run the final
device off battery power, or put one in every home. Admittedly the
100mA USB limit may be a factor if there are a decent number of
chips involved, but that's just one option for power.
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