Transistor Switching Circuit for GPS Device

Hello everyone!

I want to turn on/off my GPS(SKM53) using transistor based circuit as it consumes too much current 45mAh so i want to save my battery.

I need help in solving this problem keeping in mind the following limitations :

1. My battery voltage is 3.4v
2. GPS current requirement is 45-50mA
3. GPS voltage requirement is 3.2v(minimum)

I tested some transistor switching configurations and results are below :

Transistor : 2N3904(I have this general purpose so i decided to randomly test it)

1. I tried connecting load(gps device) directly with the emitter of transistor and applied vcc on collactor and switching signal at base with 1k resistor(also tested without 1k resistor) there is alot more voltage drop its like if signal at base is 3v the volatge on GPS is 0v but when volatge on base is 0v the volatge on gps is 2.5v(or less) i didn't checked it as this configuration didn't work for me.

2. So then i tested a circuit(attached image), this configuration gave me maximum voltage on GPS device(3.0v when base voltage is 0v and 0v on gps when base voltage is 3v).


if i add too small resistance with collator (1ohm or 10ohm or 20ohm) it started getting hot immediately so i attached 4-100ohm resistance in parallel to get the minimum resistance at collactor.

Kingly suggest me a good solution/circuit using transistor to switch my GPS load device on/off ( I dn't know the load resistance of my device(however i attached my DMM on VCC and GND pins on my GPS and it showed me approx resistance of 18k but i dnt think its correct)

I am not good with transistors. So kindly help me with circuit diagram. Ideally i need a switching circuit with zero voltage drop and minimum switching current and also full filling the 50mA load current when switch is active.

I bought a 3v relay as well for this purpose
**broken link removed**

But i am unable to understand this relay it has 10 pins. Dn't know how to switch it. I applied 3.3v on coil pins but it didn't switch(i think the reason is as its datasheet says maximum switching voltage is 2.25v so i threw it away)

Regards.

You would be better off, I suspect, using a MOSFET as a switch as the voltage drop across a transistor would drop the voltage below GPS voltage requirement. I am sure you can find many MOSFET switch circuits on the internet.