Hi

I ma just familiar with the transistors and not very expert of it. At the moment i need to control 12V's through microcontroller pin. here is the circuit i tried to used.

i have a BC307 transistor. microcontroller pin is connected to 10K resistor whcih is connected to + of 8V2 diod and - of the diod goes to Base of transistor. there is 10K oham resistor between Base and Enode. +12 Vs goes to Enode. output is available from Cathod.


now the problem with this circuit is that some times its working fine with the micrcontroller but some times it does not. output stuck at 12V. Please suggest me a circuit whcih can control 12V power supply. this output will goes to some external security PIR's (1-8 in number and which require 12 V's) which i want to turned ON of OFF through this circuit.

Also please let me know who to control the amount of current through this circuit.

Shahzad.