Hi!
I built a dark circuit - "Dunkelschaltung" which should light a LED on 9V when it is dark.
I used a BC547 Transistor and some resistors. 1k on the Base and 1x 100k for sensitivity of the circuit.
Everything went fine. When the LDR was covered the LED turned on.
pic1
NOW I wanted to replace the single led with a parralell array, of about 30 leds. (4 Leds serial and those series parallel)
This array is already built and works perfectly with 9V.
I measured voltage between + and the collector of my BC547 (where the LED is connected) ... correct 9V. (when LDR is covered - 0 if its in light)
pic2
But if I remove the single LED and replace it with the connection wires of my array nothing happens.... the array does not light up even if I use an external power supply instead of the battery.
pic3
What am I doing wrong?
Answers german or english
yours
Martin