Hello everyone, this is my first time building a circuit and I'm having trouble understanding transistors. I don't know which values in the datasheet tell me how many volts and amps I need to turn on the transistor.
I am trying to create a 16x16 RGB Led matrix controlled with 8-bit shift registers (74HC595N). 1 output from the shift registers switches on a row of LEDs, if all columns are enabled that would be 48 LEDs.
With a 5V power supply I think this gives a total of almost 1A over the row transistor. Could I use a TIP120 with the base voltage coming from the shift registers, or would I have to amplify the logic current first?
I was also thinking about using 2 of the PN2222A per row so they each only had 24 LEDs which should require less volts and amps on the base pin...
The columns are controlled by a 2N3904, only 1 LED should be on at a time in a column so I'm less worried about this transistor. I want to control all of the transistors with signals directly from the shift registers (with 1 resistor), is this reasonable?
I haven't built any circuits before so I expect to be totally off, I've tried doing the math but I'm not really sure what values to use from the datasheets.
My schematic for the 2 transistors per row (24 LEDs) idea.
I'm basing this off of Kevin Darrah's 8x8x8 cube http://www.kevindarrah.com/?p=1424 which has 192 LEDs per "row" since my power needs are smaller I'm trying to reduce the complexity of the circuit.
I am trying to create a 16x16 RGB Led matrix controlled with 8-bit shift registers (74HC595N). 1 output from the shift registers switches on a row of LEDs, if all columns are enabled that would be 48 LEDs.
With a 5V power supply I think this gives a total of almost 1A over the row transistor. Could I use a TIP120 with the base voltage coming from the shift registers, or would I have to amplify the logic current first?
I was also thinking about using 2 of the PN2222A per row so they each only had 24 LEDs which should require less volts and amps on the base pin...
The columns are controlled by a 2N3904, only 1 LED should be on at a time in a column so I'm less worried about this transistor. I want to control all of the transistors with signals directly from the shift registers (with 1 resistor), is this reasonable?
I haven't built any circuits before so I expect to be totally off, I've tried doing the math but I'm not really sure what values to use from the datasheets.
My schematic for the 2 transistors per row (24 LEDs) idea.
I'm basing this off of Kevin Darrah's 8x8x8 cube http://www.kevindarrah.com/?p=1424 which has 192 LEDs per "row" since my power needs are smaller I'm trying to reduce the complexity of the circuit.