switching problems with bjt

[bidex]

Hi, i have a problem in using a C1815 xsistor,when d emitter is earthed it prevents my cct 4rom switching.Will a mosfet solve dis as i cannot put an emitter resistor to maintain my time constant.Can i gnd d source directly?The switching is to be at d same time with another switch,one to produce a siren sound and d other 4 wave shaping to make d sound perfect.Also what kind of mosfet do i use?

 

[audioguru]

Please use proper English with complete spelling for all words.
Attach your schematic so we can see what you are trying to talk about.

 

[penoy_balut]

you are probably talking about modulation of your siren sound, C1815 can do the job, but audioguru cannot help without a schematic.

 

[tunedwolf]

d frst ting ya nd tu du iz cm un ik 8 wit ot he rz n a clr mn nr