How do I identify the correct power source for a circuit?

Thread Starter

cncmaker

Joined Nov 20, 2019
2
I've got hold of a Bluetooth controller module. But I do not know whether is should be supplied with A/C or D/C voltage (and if DC then what voltage). Is there a way to go about determining this?

I've got a picture of the PCB. 2 wires are the supply and the 3rd wire is a switched live activated when bluetooth remote control is pressed.

pcb.PNG
 

SLK001

Joined Nov 29, 2011
1,529
Well, you start by getting datasheets of the devices on your board. The N52632 is a Bluetooth controller that has a DC input voltage range of 1.7 to 3.6V. The SOT89 device looks like an on-board voltage regulator, so your input at the connector has to be high enough to allow the regulator to regulate - probably 5V or so.

So, download the datasheet for the N52832, find the pinout to locate the VCC lines, then hookup a variable DC supply to the DC input line and, while monitoring the DC VCC voltage on the BT chip, slowly increase the input voltage until the VCC pin reaches a plateau. My guess is that your input DC voltage will be either 3.3V or 5V.
 
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