Hello my Friends, it's my first post.
I would like to add some logic circuit (AND and INVERTER) to output of LM3914 driver.
I'm beginner so please don't be mad if i done something wrong.
Here is my project:
Few facts)
LM is configured to BAR mode.
Lowest LED (output 1) light when voltage is 10.5V.
I would like, to use that low led as logic output, i added a transistor (i'm not sure if i do this in right way).
After that transistor i hope to have 5V or 0V for logic control.
Than i have simple AND gate (74LS09) with 2 inputs.
First input is from that transistor above (when LM3914 detect above 10.5V)
Second come from push-switch AND through diode from output of LOGIC gate (when it have 5V at output).
I hope, this will work:
When i push the switch and have 5V in first input.
Logic gate output 5V on output.
That output come back to input of logic gate.
And I will have gate at "truth" until LM3914 stop sending signal to output 1.
Then AND gate will have 0 on first input and 5 on output, what will cause (AND) not truth, and shut down gate.
When LM3914 send signal, logic gate will be close, because of missing second input (user will have push button).
Logic 5v, from AND gate go to INVERTER (74HC04) what will revers 1 to 0 and 0 to 1.
I hope it mean: when logic gate will have 5V on output after inverter i will have 0V, what's mean transistor will not allow LED to flash what's mean everything is OK.
When at GATE output it will be 0, at output of inverter will be 5v, what's mean transistor should allow current flow to diode what will signalize to user: "no power at output"
Gate output will also send signal to another transistor, what will controll 12V relay.
For relay output will be connected device what consume large amout of power (few A).
This device will start work after user push button, and voltage is above 10.5V.
When it will drop under that voltage, device will be disconnected.
If voltage (after disconnecting load will rise) relay won't switch... it will wait for user "reset".
Is this might work ?
If i made something wrong please correct me.
regards
I would like to add some logic circuit (AND and INVERTER) to output of LM3914 driver.
I'm beginner so please don't be mad if i done something wrong.
Here is my project:
Few facts)
LM is configured to BAR mode.
Lowest LED (output 1) light when voltage is 10.5V.
I would like, to use that low led as logic output, i added a transistor (i'm not sure if i do this in right way).
After that transistor i hope to have 5V or 0V for logic control.
Than i have simple AND gate (74LS09) with 2 inputs.
First input is from that transistor above (when LM3914 detect above 10.5V)
Second come from push-switch AND through diode from output of LOGIC gate (when it have 5V at output).
I hope, this will work:
When i push the switch and have 5V in first input.
Logic gate output 5V on output.
That output come back to input of logic gate.
And I will have gate at "truth" until LM3914 stop sending signal to output 1.
Then AND gate will have 0 on first input and 5 on output, what will cause (AND) not truth, and shut down gate.
When LM3914 send signal, logic gate will be close, because of missing second input (user will have push button).
Logic 5v, from AND gate go to INVERTER (74HC04) what will revers 1 to 0 and 0 to 1.
I hope it mean: when logic gate will have 5V on output after inverter i will have 0V, what's mean transistor will not allow LED to flash what's mean everything is OK.
When at GATE output it will be 0, at output of inverter will be 5v, what's mean transistor should allow current flow to diode what will signalize to user: "no power at output"
Gate output will also send signal to another transistor, what will controll 12V relay.
For relay output will be connected device what consume large amout of power (few A).
This device will start work after user push button, and voltage is above 10.5V.
When it will drop under that voltage, device will be disconnected.
If voltage (after disconnecting load will rise) relay won't switch... it will wait for user "reset".
Is this might work ?
If i made something wrong please correct me.
regards
Last edited by a moderator: