brain-dead
Junior Member level 3
Hi Everyone,
I have a Tx module on 433 Mhz. I want to use this module in a project, however I want maximum battery power, so I would like to be able to turn off Vdd to prevent Tx module quiescent current. The project runs on 2xAA batteries
I am using an MCU output to turn on an NPN, which then turns on the PNP as it's collector load.
The problem is that when the PNP is on, the voltage is there, all seems ok, but the Tx module will not work properly. I have used a 10K from the MCU to NPN and again a 10K from the PNP base to NPN collector.
I have removed the PNP and shorted the collector and emitter connections with a wire and all works perfectly!!
Do I need a special type of transistor to be able to effectively switch on/off an Rf load?
I have tried variants of PNP transistors but they are cheapy 2n3906 equivalents pretty much.
Any help would be much appreciated
I have a Tx module on 433 Mhz. I want to use this module in a project, however I want maximum battery power, so I would like to be able to turn off Vdd to prevent Tx module quiescent current. The project runs on 2xAA batteries
I am using an MCU output to turn on an NPN, which then turns on the PNP as it's collector load.
The problem is that when the PNP is on, the voltage is there, all seems ok, but the Tx module will not work properly. I have used a 10K from the MCU to NPN and again a 10K from the PNP base to NPN collector.
I have removed the PNP and shorted the collector and emitter connections with a wire and all works perfectly!!
Do I need a special type of transistor to be able to effectively switch on/off an Rf load?
I have tried variants of PNP transistors but they are cheapy 2n3906 equivalents pretty much.
Any help would be much appreciated