I made a regulated variable power supply with an output of 0-30V and 1.5A max. I want to put a voltage level indicator using a LED. I saw a sample in a book with a bipolar junction transistor and a zener diode but i cannot fully draw the circuit.
Please help me to design a circuit of this when every 3V from the output of power supply 1 LED will turn on. Then when 30V from the output, 10 LEDs will turn on.
The easiest is to do this is with the Nat. Semi. LM3914. All the info you need is in the datasheet. I, however would use an inexpensive ($20 or so) digital with 3 1/2 digits, set to 200V readout. E
Sorry im a ultimate noob in reading datasheet. I used the ericgibbs calc, but i dont know now how will i put a a voltage in V+ and in RHi. Can you help me with these? I really need a Led Voltage Level Indicator. Thanks.
Sorry im a ultimate noob in reading datasheet. I used the ericgibbs calc, but i dont know now how will i put a a voltage in V+ and in RHi. Can you help me with these? I really need a Led Voltage Level Indicator. Thanks.
i have with me a adjustable voltage supply, may Vout is from 1.25-30V using LM317. Please help me to design a circuit of this when every 3V from the output of power supply 1 LED will turn on. Then when 30V from the output, 10 LEDs will turn on. Thank you.
Here is my designed circuit after using the simulation for lm3914. When im using bargraph mode, the 10 LED are not working perfectly working. The LEDs are mostly dim. Please see my attachment.
What's wrong with my circuit?
To those who helped me, thank you so much. I've come up to this circuit design and it running in my proteus. But i would like to ask for you spare time to check my design. Here it is.
I need to transfer this in pcb as soon as possible because the submission of this is nearly approaching.
hi,
That circuit is NOT suitable, there is NO mains transformer shown, also there are errors in the remainder of the circuit.
You require an mains isolated power supply that can supply a DC voltage at 0.25A , the DC voltage of the supply can be from 9V to 20V.
Let me know which power supply you have available and will post a circuit diagram.
If you rectify and smooth 24Vac you will have a DC voltage of 35Vdc, the LM3914, is rated at 25Vdc max.
Oh. Can i just put a resistor so that i can i can put 25Vdc max to the LM3914. If not, so i can't use LM3914 for a LED Voltage level indicator. My power supply is rectifying 24Vac and the out put is from 1.25-30V 1A. What will i do to put a LED Voltage indicator? Using BJT with zener? Please help me with the calculations.