LM358 circuit

Other Hardware General Electronics
5

Its been a long time since I worked with an LM358 and I don't recall the actual minimum output voltage. However I'm pretty sure the output being a PNP will not go much below 0.8 Volts. This level can turn on your BC547.

You could:

  1. add a diode or two in series with the LM358 output.

  2. add a resistor from the base of the BC547 to ground, perhaps 5k or so.