Both pin 2 and pin 4 should go to negative, it looks like only pin 2 does.
pin 9 should go to positive for a bargraph or do not connect for a dot mode.
Make sure the LED's are the right way round >Flatside of the leds to the Chip other side to positive.
A voltage on the wire to pin 5 should light the leds. You can try this by connecting another variable resistor (potentiometer) one side to positive(+) one to Negative(-) and then the middle to pin 8
this will allow you to adjust the voltage from @ 0 to @9 volts and see the leds light.
once this works we can add the few parts needed to make it work on music signals
alan
pin 9 should go to positive for a bargraph or do not connect for a dot mode.
Make sure the LED's are the right way round >Flatside of the leds to the Chip other side to positive.
A voltage on the wire to pin 5 should light the leds. You can try this by connecting another variable resistor (potentiometer) one side to positive(+) one to Negative(-) and then the middle to pin 8
this will allow you to adjust the voltage from @ 0 to @9 volts and see the leds light.
once this works we can add the few parts needed to make it work on music signals
alan
staring at this I agree I think pin8 is grounded, my first guess was pin 9 grounded.
So Disconnect the wire from pin 8 to ground
Pin8 connects to the Potentiometer
Pin 8 also goes to one end of the resistor, the other end to pin 7. I think that is done on the board.
One suggestion to the OP make all + leads red and all - leads blue this makes it easier to troubleshoot and less likely to connect the wrong way.
Try and find a cheap digital multimeter they can be had for a few euros if you look.
So Disconnect the wire from pin 8 to ground
Pin8 connects to the Potentiometer
Pin 8 also goes to one end of the resistor, the other end to pin 7. I think that is done on the board.
One suggestion to the OP make all + leads red and all - leads blue this makes it easier to troubleshoot and less likely to connect the wrong way.
Try and find a cheap digital multimeter they can be had for a few euros if you look.
Last edited:
I know this probably sounds obvious (this is aimed at lukutis 
) but it can help to look at each pin in turn on the IC starting at pin 1 and then confirming and checking it goes exactly where it should. Go around the IC methodically and tick them off as you check each one.
Just looking at it all as a whole and you miss things.
) but it can help to look at each pin in turn on the IC starting at pin 1 and then confirming and checking it goes exactly where it should. Go around the IC methodically and tick them off as you check each one.Just looking at it all as a whole and you miss things.
well we have to assume that all your connections are good (some breadboards will give you connection problems especially if you use different diameter wires in adjacent holes)
if pin 2 and 4 are connected and 2 see's ground then 4 should be grounded (only real way to know is to verify with a multimeter set to low ohm's scale)
tying pin 8 to the pot wiper will change the sensitivity (which from what your telling us isn't sensitive enough)
if pin 2 and 4 are connected and 2 see's ground then 4 should be grounded (only real way to know is to verify with a multimeter set to low ohm's scale)
tying pin 8 to the pot wiper will change the sensitivity (which from what your telling us isn't sensitive enough)
The original diagram shows the middle leg of the variable resistor connecting to one end of the variable and ground. The other end of the variable goes to pin 8
As turk suggests connect pin 9 to positive to make a bargraph.
the meter is quite sensitive without an opamp and will work off the output of a soundcard.
To make it work though I feel the original circuit is not much use and you need a diode, a capacitor and 2 resistors, see image attached.
This will give only positive voltage to the VU meter, the value of the capacitor will alter the decay time of the bar graph, try 0.1uf > 1 uf the larger the value the slower the meter.
As turk suggests connect pin 9 to positive to make a bargraph.
the meter is quite sensitive without an opamp and will work off the output of a soundcard.
To make it work though I feel the original circuit is not much use and you need a diode, a capacitor and 2 resistors, see image attached.
This will give only positive voltage to the VU meter, the value of the capacitor will alter the decay time of the bar graph, try 0.1uf > 1 uf the larger the value the slower the meter.
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.