7 segment LED displays - UK Vintage Radio Repair and Restoration Discussion Forum

joebog1 · 14th Oct 2021, 2:04 am

I wonder if anyone has an idea about high output seven segment LED displays. I have purchased a job lot of 10 display module kits that are generally used with red LED displays.
I am looking for high output .56" GREEN displays, to make viewing voltage and current distinctly different and "visual at a glance". I would prefer analogue meters but they cost about ten times more than 7107 chip kits.

So my question is: Can anybody recommend a common anode green .56" display that I can use. I have already bought some, ( several sources ) but as green leds require considerably different voltages and currents to red leds they fall somewhat short of what I am looking for. The brightness of the red LEDS supplied is excellent and I would like to get a bit closer to the two displays being close to equal brightness.

The displays provided in the meter kits are:
5161BS ( probably locally procured in China for the kits ).
.56 inch seven segment with right hand decimal dot.
I need a different colour. Please.
I "dont think" the current from the 7107 can be increased.

Thanks in advance

Joe

Herald1360 · 14th Oct 2021, 10:23 am

Could you not add buffers between the segment outputs from the 7107 and the LED display to get higher current drive to those green LED?

Oldcodger · 14th Oct 2021, 11:22 am

Possibly telling Granny how to suck eggs, but mentioning buffers. How about either a CD4049 OR CD4050. The difference is that the 4049 is inverting. The only problem is that each IC contains 6 buffers, so you will need two and the unused inputs need to be tied via a large resistor to either supply line.

joebog1 · 14th Oct 2021, 11:09 pm

Thanks gents, yes I could add buffers but the reason I have gone this way is to save Vero boarding or designing/making PCB's to fit. I want to use these meters in my valve tester and it's complicated enough already!!. These kits cost $9 aussie ( about 4 1/2 quid ) and are very well presented. All the critical resistors are 1% metal films, decouplers are all monolithic ceramic with known makers' brands on them and the two electros used to generate the negative supply are rated @ 105C. Even the 7107's are made by ICL.

I am trying to cheat I guess, and avoid the manufacturing bit.

I will see if somebody has more experience with these displays and knows of a high or at least higher output version.

14th Oct 2021, 2:04 am	#1
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	7 segment LED displays I wonder if anyone has an idea about high output seven segment LED displays. I have purchased a job lot of 10 display module kits that are generally used with red LED displays. I am looking for high output .56" GREEN displays, to make viewing voltage and current distinctly different and "visual at a glance". I would prefer analogue meters but they cost about ten times more than 7107 chip kits. So my question is: Can anybody recommend a common anode green .56" display that I can use. I have already bought some, ( several sources ) but as green leds require considerably different voltages and currents to red leds they fall somewhat short of what I am looking for. The brightness of the red LEDS supplied is excellent and I would like to get a bit closer to the two displays being close to equal brightness. The displays provided in the meter kits are: 5161BS ( probably locally procured in China for the kits ). .56 inch seven segment with right hand decimal dot. I need a different colour. Please. I "dont think" the current from the 7107 can be increased. Thanks in advance Joe

14th Oct 2021, 10:23 am	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: 7 segment LED displays Could you not add buffers between the segment outputs from the 7107 and the LED display to get higher current drive to those green LED? __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

14th Oct 2021, 11:22 am	#3
Oldcodger Nonode Join Date: Oct 2014 Location: West Midlands, UK. Posts: 2,181	Re: 7 segment LED displays Possibly telling Granny how to suck eggs, but mentioning buffers. How about either a CD4049 OR CD4050. The difference is that the 4049 is inverting. The only problem is that each IC contains 6 buffers, so you will need two and the unused inputs need to be tied via a large resistor to either supply line.

14th Oct 2021, 11:09 pm	#4
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: 7 segment LED displays Thanks gents, yes I could add buffers but the reason I have gone this way is to save Vero boarding or designing/making PCB's to fit. I want to use these meters in my valve tester and it's complicated enough already!!. These kits cost $9 aussie ( about 4 1/2 quid ) and are very well presented. All the critical resistors are 1% metal films, decouplers are all monolithic ceramic with known makers' brands on them and the two electros used to generate the negative supply are rated @ 105C. Even the 7107's are made by ICL. I am trying to cheat I guess, and avoid the manufacturing bit. I will see if somebody has more experience with these displays and knows of a high or at least higher output version.