Hi all. I am using an LMC555 for a monostable circuit in a LV project. The chip is set up to operate a buzzer via pin 3 every time I trigger it. I have been forced to use a transistor to drive the buzzer because the voltage level at the output pin is too low. The supply voltage is about 3.2V (2 X AAA) and the datasheet specifies only a small voltage drop at the output. My buzzer can sound at 1V but when I connect it between pin-3 and Ground I get nothing. Measuring the voltage across it when the LMC555 is triggered I get about 1.5V. If I replace the CMOS 555 with a normal 555 timer (~NE555) the circuit works fine. I don't want to use a normal 555 timer though because it won't work when the batteries fall below 3V, draws too much current, and requires two more capacitors in my circuit.
So my issues are: - Why am I getting such a small output voltage in comparison to the supply?
- Why isn't my buzzer working with the LMC555 even though it can sound at 1.5V?
Thanks, Trevor G.
So my issues are: - Why am I getting such a small output voltage in comparison to the supply?
- Why isn't my buzzer working with the LMC555 even though it can sound at 1.5V?
Thanks, Trevor G.