Simple Digital Potentiometer with DS1869

Description: The experimenter's pot is a solid state potentiometer using Dallas semiconductor's DS1869 and National's LM78L05, two electrolytic capacitors, two small push button switches, and two optional Molex connectors. This project is very useful, especially in finding the right value of resistor in experiments. It can be attached to projects that use a potentiometer or trimmer. There are three types of DS1869: DS1869-10, which is 10K; DS1869-50, a 50K version; and DS1869-100, the 100K version. The circuit is powered from a 9V power supply (any 9V power source will work, as long as the current rating is not less than 25mA), stepped down to 5V by the LM78L05 IC and two filter capacitors—one for the input and one for the output. The wiper arm's position is adjusted by pressing SW2 to increase the resistance from the wiper arm to the high terminal, and SW1 to decrease it, similar to an ordinary mechanical potentiometer. Adding resistance to the high terminal decreases the resistance to the low terminal.

Parts List:
C1 10uF/16V Electrolytic capacitor
C2 0.01uF/50V Ceramic capacitor
U1 LM78L05
U2 DS1869 (see notes)
SW1,SW2 Small push button switch

Notes: The maximum wiper current allowed through the DS1869 is only 1 milliamps. There are three types of DS1869: DS1869-10 for a 10K version, DS1869-50 for a 50K version, and DS1869-100 for the 100K version.

The circuit design for the experimenter's potentiometer utilizes a solid state approach, incorporating the DS1869 digital potentiometer, which provides a reliable and adjustable resistance in a compact form factor. The DS1869 operates by controlling the wiper position through digital signals, allowing for precise adjustments in resistance values. The inclusion of the LM78L05 voltage regulator ensures that the circuit receives a stable 5V supply, essential for the proper functioning of the DS1869, which is sensitive to voltage variations.

The two electrolytic capacitors, C1 and C2, serve as filter capacitors that smooth out the input and output voltages, respectively, thereby enhancing the stability of the power supply to the DS1869 and ensuring that the wiper adjustment does not generate noise or fluctuations in the output signal. The push button switches, SW1 and SW2, provide a user-friendly interface for adjusting the potentiometer's wiper position. SW1 is used to decrease the resistance by moving the wiper towards the low terminal, while SW2 increases the resistance by moving it towards the high terminal.

The optional Molex connectors offer versatility for connecting the potentiometer to various projects, facilitating easy integration into existing circuits. The design is particularly advantageous for applications requiring frequent adjustments to resistance values, such as in experimental setups or prototyping environments. The choice of the DS1869 variant allows for flexibility in resistance selection, catering to different application needs while maintaining a maximum wiper current of 1 mA to ensure the longevity and reliability of the device.The experimenter's pot is a solid state potentiometer using Dallas semiconductor?s DS1869 and National?s LM78L05 two electrolytic capacitor two small push button switch and two optional Molex connector. this project is very useful especially in finding the right value of resistor in your experiments, you can attach this circuit to your next project that uses a pot or trimmer cause there are three types of DS1869 these are: DS1869-10 which is 10K.

DS1869-50 a 50K version. DS1869-100 the 100K version As you can see, the circuit is powered from a 9V power supply (actually any 9V power source will work, as long as the current rating is not less than 25mA) stepped down to 5V by the LM78L05 IC and two filter capacitor one for the input and one for the output, the wiper arm?s position is stepped by pressing SW2 for adding the resistance of wiper arm to high terminal and SW1 for decreasing just like an ordinary mechanical potentiometer adding the resistance to high terminal decreases the resistance to low terminal. Parts List Parts List: C1 10uF/16V Electrolytic capacitor C2 0.01uF/50V Ceramic capacitor U1 LM78L05 U2 DS1869 (see notes) SW1,SW2 Small push button switch Notes: The maximum wiper current allowed through the DS1869 is only 1 milliamps.

There are three types of DS1869 DS1869-10 use this chip if you want to make a 10K version DS1869-50 for a 50K version pot. DS1869-100 for the 100K version