Hi guys,
I have a 3V battery source. My device runs using 1.5V only. So how do I convert the 3V source to 1.5V?
Will a voltage divider work properly?
I know I could just use a single AA battery but I NEED to use the 3V battery voltage..pls dun ask why cos It is quite complicated 
So any suggestions as to how to convert the 3V to 1.5V?
You can get DC-to-DC Converter modules for almost any combination of voltages.
For example you can get this unit for $2.50:
Input voltage is 2 to 6 and output is 1.5V 600mA.
Depending on your circuit, why not use a Zener Diode? and clamp the voltage?
kurtselva:
I have a 3V battery source.
If you're using existing battery technology you most likely have a battery source that goes from 3.2V down to 2.2V as the battery is used up.
kurtselva:
So any suggestions as to how to convert the 3V to 1.5V?
There a lot of ways to do it but the best answer will depend on how many amps you need and how power-efficient it needs to be.
cjdelphi:
Depending on your circuit, why not use a Zener Diode? and clamp the voltage?
Was thinking about this as well but if that is the case, I have to use a zener diode of value ard 1.5V right?
I doubt there is a 1.5V zener diode..Correct me if I am wrong
fungus:
There a lot of ways to do it but the best answer will depend on how many amps you need and how power-efficient it needs to be.
I will only be needing about 60mAmps to turn a dc motor. And the dc motor will only rotate for like 5 seconds every 6 hours..
Run the motor with a resistor in series to limit the current to 60 mA.
Otherwise, since we're in a Arduino-forum - PWM the motor.
// Per.
Zapro:
Run the motor with a resistor in series to limit the current to 60 mA.
That would work if the battery voltage was a constant, but it isn't.
Then give us some more details on the motor, the batteries etc.
// Per.
kurtselva:
fungus:
There a lot of ways to do it but the best answer will depend on how many amps you need and how power-efficient it needs to be.I will only be needing about 60mAmps to turn a dc motor. And the dc motor will only rotate for like 5 seconds every 6 hours..
kurtselva:
fungus:
There a lot of ways to do it but the best answer will depend on how many amps you need and how power-efficient it needs to be.I will only be needing about 60mAmps to turn a dc motor. And the dc motor will only rotate for like 5 seconds every 6 hours..
In that case a couple of diodes ought to do it.
A regular diode will drop 0.7 Volts when you apply a voltage across it. Two in series is 1.4V - should be enough for the motor.
Call the positive connection of your motor "M".
Use a PNP transistor (eg. BC327) between your battery '+' and 'M' to switch the motor on.
Connect a couple of diodes in series from 'M' to ground. The diodes will shunt away anything over 1.4V. It's hugely inefficient, but... for 5 seconds every six hours, who cares?
You should probably add a resistor between the PNP transistor and 'M', too, to prevent a complete short-circuit of the battery when it switches on. 3 Ohms, 500mW is about right according to my calcs.
Edit: Math for the resistor so you can double-check me:
The two diodes+BC327 transistor will drop 2.1V between them. The battery starts at 3V and goes downwards...
At 3V the resistor sees 0.9V (ie. 3V-2.1V). It allows 300mA to pass - should be OK for the battery.
At 2.3V the resistor sees 0.2V. It allows 60mA to pass - still enough for the motor.
The circuit works down to approx. 2.3V (where the battery is basically dead).
Feel free to correct me...
fungus:
Zapro:
Run the motor with a resistor in series to limit the current to 60 mA.That would work if the battery voltage was a constant, but it isn't.
I'm not trying to be argumentative here. Just curious... How is a pair of diodes better?
fungus:
In that case a couple of diodes ought to do it.A regular diode will drop 0.7 Volts when you apply a voltage across it. Two in series is 1.4V - should be enough for the motor.
Call the positive connection of your motor "M".
Use a PNP transistor (eg. BC327) between your battery '+' and 'M' to switch the motor on.
Connect a couple of diodes in series from 'M' to ground. The diodes will shunt away anything over 1.4V. It's hugely inefficient, but... for 5 seconds every six hours, who cares?
You should probably add a resistor between the PNP transistor and 'M', too, to prevent a complete short-circuit of the battery when it switches on. 3 Ohms, 500mW is about right according to my calcs.
Edit: Math for the resistor so you can double-check me:
The two diodes+BC327 transistor will drop 2.1V between them. The battery starts at 3V and goes downwards...
At 3V the resistor sees 0.9V (ie. 3V-2.1V). It allows 300mA to pass - should be OK for the battery.
At 2.3V the resistor sees 0.2V. It allows 60mA to pass - still enough for the motor.The circuit works down to approx. 2.3V (where the battery is basically dead).
Feel free to correct me...
Actually there are more components connected to the device..And all of them use 1.5V
Basically, there is a timer clock, a dc motor and some component (which i do not know what it is) that is connected to the motor. When the "thing" is like on, it will rotate the motor until it becomes off.
I have attached a photo of the device and its internal connections..
Anyway, could a 1.5V regulator be used?
Doc1.pdf (254 KB)
kurtselva:
Actually there are more components connected to the device..And all of them use 1.5V
...and none of them were worth mentioning before?
kurtselva:
Anyway, could a 1.5V regulator be used?
Sure, go ahead.