10. Output Devices¶
This week’s group assignment was to measure the power consumption of output devices.
Measuring the Power consumption¶
1. Measure the voltage (V) and current (mA) of an LED with a multimeter¶
when each resistor is connected to the LED as below:
(1) 1 resistor
(2)Two resistors connected in seriesM
(3) 2 resistors connected in parallel
The voltage is 5V and one resistor is constant at 330Ω.
For LEDs, the voltage is constant and does not change even if the current changes.
Logic value
| Number of resistors | Current of the entire circuit | Resistor value | Voltage of LED |
|---|---|---|---|
| (1) One resistor | 10mA | 330Ω | 2V |
| (2)Two resistors in series | 5mA | 660Ω | 2V |
| (3)2 resistors (parallel) | 18mA | 165Ω | 2V |
Result
| Number of resistors | Current of entire circuit | Resistor Value | LED voltage |
|---|---|---|---|
| (1) One resistor | 9.2mA | ||
| (2)Two resistors (in series) | 4.5mA | ||
| (3)Two resistors (in parallel) | 1.8mA |
It was confirmed that there was no significant deviation from the theoretical values.
2. Check how much the current varies depending on the voltage and the number of Stepping motor¶
Device
With a regulated power supply, the following can flow
- Current: 0-5 amperes
- Voltage: 0-20 volts
- Voltage can be adjusted
- Adjust the current so that the resistance value does not change when the voltage changes (used to ensure that the movement of the device, such as a motor, does not change).
Theory
- Current increases as voltage decreases.
- When the number of motors increases, the current increases
Result
| Current at 12.4V voltage | Current at voltage 0.9V | |
|---|---|---|
| One motor | 0.1A | 0.13A |
| Two motors | 0.14A | 0.18A |
The following was confirmed
- Current increases as voltage decreases
- As the motor increases, the current increases