How to use the cartridge heater wiring?

Cartridge heater wiring

 

First, the concept of series circuit of resistive electric heating elements

 

Series circuit: A circuit in which two or more resistive electric heating elements are sequentially connected to make a current having only one path of the circuit.

 

Second, the characteristics of the resistor series circuit

 

Let the total voltage be U, the current be I, and the total power be P.

 

1. Current characteristics: The currents in the series circuit are equal. I1=I2=I3=I

 

2. Voltage characteristics: The voltage across the series circuit is equal to the sum of the voltages across the circuit. U=U1+U2+U3

 

2. Equivalent resistance (total resistance): R = R1  R2  R3

 

Tip: The resistance of the resistor is larger and larger. When n heating elements with equal resistance are connected in series, the equivalent resistance R=nRo

 

3. Partial pressure relationship:

 

3. Power allocation:

 

Special case: When two resistors R1 and R2 are connected in series, the equivalent resistance R = R1  R2, there is a partial pressure formula

 

Experiment: Measure the total resistance of R1 and R2, R3 in series.

 

Q: What are the methods and principles of the experiment?

 

A: Measure the resistance with voltammetry. As long as the total voltage across the series resistors of R1 and R2 and R3 is measured with a voltmeter and the current through the series resistor is measured with an ammeter, the total resistance of R1 and R2, R3 in series can be calculated according to Ohm's law.

 

Students are required to design an experimental circuit that measures the total resistance of three series resistors (R1 = 2 ohms, R2 = 4 ohms, R3 = 2 ohms). As shown in Figure 8-5.

 

conduct experiment:

 

1 Experiment with the requirements of voltammetric resistance measurement.

 

2 Measure the total resistance R of R1 (2 ohms) and R2 (4 ohms) and R3 (2 ohms) in series.

 

3 Fill in the conclusions of the experiment in the text.