Voltage Regulator 5V-20V Project.

If you are looking for a low drop voltage regulator that is able to provide a power supply

of 1A with an output voltage of between 5V and 20V DC, National Semiconductor LM2941 Low Dropout Adjustable Regulator is one that you can choose to use. It has a typical dropout voltage of 0.5V which means that the input supply need only have to be 0.5V DC more than the desired output voltage. Its other features include internal short circuit current limit and reverse battery protection. As shown in the schematic below, the regulator has 5 pins which consists of the ON/OFF control, Input Voltage, Output Voltage, Ground and Adjustable pins. ON/OFF is used for the purpose of switching on and off of the regulator. The capacitors C1 and E1 are to be placed as close as possible to the regulator.

Download this schematic diagram.

The output of the circuit can be varied by varying the value of potentiometer VR1 from 5V DC to 20V DC. The input voltage is limited from 5.5V DC to 30V DC. Resistor R1 must be greater than 1K. The value of the VR1 that needs to be set is calculated from the formula given below:

VR1 = R1[(Vout/1.275) - 1] ohm

If R1=1K, Vout = 5V, VR1 should be set to 2.9K ohm.

If R1=1K, Vout = 20V, VR1 should be set to 14.7K ohm

Datasheet semiconductor component download. (PDF Format)

1. LM2941CT

Low Impedance Microphone Amplifier

You can download the schematic, pcb layout and component list from here





Download this schematic diagram.

This circuit is a microphone amplifier for use with low impedance (~200 ohm) microphones.
It will work with stabilized voltages between 6-30VDC. If you don’t build the impedance adapter part with T1, you get a mic-amp for higher impedance microphones. In this case, you should directly connect the signal to C7.

Component list:

R1=15k		C1= 3k9		U1= TL081
R2= 150k		C2= 100u		D1= 1N4148
R3= 2k2		C3= 22u		CN1= SIL6
R4= 820		C4= 4u7
R6= 10k		C5= 470u
R7= 10k		C6= 10u
P1= 1M		C7= 100n
		C8= 47u UNIPOLAR