Hello,
This is my first post. I am trying to build a voice-activated switch circuit. That is, when you speak into the microphone it will turn on an LED for some time (based on an RC circuit), then automatically shut off. So the LED should not display any fade-out, but that's not a big deal if it does.
Requirements that I have created for this circuit:
Is there a way I can utilize these two, or maybe one more transistor, to achieve the effect I want? Or should I just get an op-amp comparator and be done with it?
Thanks.
This is my first post. I am trying to build a voice-activated switch circuit. That is, when you speak into the microphone it will turn on an LED for some time (based on an RC circuit), then automatically shut off. So the LED should not display any fade-out, but that's not a big deal if it does.
Requirements that I have created for this circuit:
- Powered by 6 AA batteries; about 6.2-7 volts single-ended supply.
- it must be extremely low power; essentially this is the on-off switch for a couple of watts of LEDs, so any drain during downtime is simply wasted power.
- extremely low cost. I could spend a buck on an op-amp and get this done with say a voltage comparator but I would like to use transistors for learning about them and because 7 cents for a2n2222 mic preamp beats 30 cents for an LF353-based one.
Is there a way I can utilize these two, or maybe one more transistor, to achieve the effect I want? Or should I just get an op-amp comparator and be done with it?
Thanks.