# How to get a dc power supply to produce 2V at 10-20 milliamps?

• pb23me
In summary, the conversation discusses the issue of a newly acquired adjustable DC power supply not producing 1-2V at small amps, and whether this is possible with a common DC power supply. The conversation also mentions the need for an opamp and a specific resistor value to achieve a current of 20mA. It is noted that the current depends on the load and supply volts. Further information about the situation is requested for better understanding.

#### pb23me

I just got a adjustable dc power supply and I cannot figure out why it will not produce 1-2V at very small amps such as 10-20 milli amps? Is this not possible with a common dc power supply? I would greatly appreciate some help with this...

What brand and make is the power supply?
What kind of load are you connection this to?

What resistor would you expect to connect across 2V to pass 20mA?

You don't need a power supply, you need an opamp.

But you can ONLY get a 2V source to produce a current of 20mA through one particular value of resistor. If you have an open circuit at the terminals then the current will be 0mA. The supply can't 'insist' on any value of current.
The current depends upon the Load and the Supply Volts:
I = V/R

Perhaps you should specify a bit more about the circumstances of the OP. I have a feeling there is something else we should know.

## 1. How do I adjust the voltage of a DC power supply?

To adjust the voltage of a DC power supply, you can use either a potentiometer or a digital control panel. With a potentiometer, you can manually turn a knob or dial to adjust the voltage. With a digital control panel, you can input the desired voltage using buttons or a keypad.

## 2. What is the maximum voltage and current that this power supply can produce?

The maximum voltage and current that a power supply can produce depends on its specifications. It is important to refer to the manufacturer's manual or datasheet to determine the maximum values. Attempting to exceed these values can damage the power supply or the equipment connected to it.

## 3. How do I calculate the current needed for a 2V output?

To calculate the current needed for a 2V output, you can use Ohm's law (I = V/R), where I is the current in amps, V is the desired output voltage, and R is the resistance of the load connected to the power supply. In this case, the resistance would be 200-100 ohms for a 10-20 milliamp output.

## 4. Can I use multiple power supplies to achieve the desired voltage and current?

Yes, you can use multiple power supplies in parallel to achieve the desired voltage and current. However, it is important to ensure that the power supplies have the same voltage and current ratings to avoid imbalances and potential damage.

## 5. How do I troubleshoot if the power supply is not producing the desired output?

If the power supply is not producing the desired output, first check to make sure it is plugged in and turned on. Then, check the voltage and current settings to ensure they are correctly adjusted. If the output is still incorrect, check for any loose connections or faulty components. If necessary, consult the manufacturer's manual or contact technical support for further assistance.