The motion sensor at the output gives 3.3V, how to raise the output to 5V?

Question

Electronics

Hello.
The SR-505 motion sensor works from 5V to 20V, I supply 9V to it, but in any case it gives 3.3V at the output, and I would like either the same input voltage or 5V. What are the simplest options for converters? There are many capacitors, transistors are in short supply, one DD127. There is also a powerbank module, to which you supply 3.7, and it gives 5V at the output. I tried it with a powerbank module, but it does not output anything at the output (0V, or 0.10-0.20V. In general, it does not work).

Answer 1

Apply this signal to the base of the NPN transistor C3779 through a resistor of approximately 150 to 310 ohms, building a simple transistor switch. You definitely need a diode connected in anti-parallel to the relay winding, otherwise the transistor will turn out to be disposable.
This is called - a key on a bipolar transistor - it describes how to accurately calculate the resistance.

Answer 2

If we exclude that dd127 is a high-voltage power transistor. Those. somewhat not for low-voltage signaling systems :)
Then it is quite possible to use this transistor in common base mode.

Answer 3

The easiest way is to use a field effect transistor. You need to turn it on according to this simple circuit, which will fit almost any medium or high power field effect transistor with an N-channel (it is unlikely that you will come across those among them that cannot withstand 9 volts or do not provide the current your relay needs).

More precisely, even more simply, since you need to apply your output 3.3 volts directly to the gate of the transistor, so all these input resistors and a capacitor are not needed (however, you can leave a resistor between the gate and source with a value of 10 kilohm). And of course, you take the relay for 6 ... 9 volts, and at the point where 12 is written, you supply your 9 volt power supply. The diode parallel to the relay winding is also almost any rectifier.
I wrote "almost any" here - this is not good for a beginner, so if you have any difficulties with the choice, write in the comments what you have found, and I will tell you if it is suitable.