The V/I convert characteristics of the AC constant current source
are good at different frequencies.
Then, the voltage signal was used as the input into the controllable constant current source
. The constant current source
output corresponding currents to the drive coil, and the coil produced a magnetic field.
The two LEDs must be driven with constant current sources
to guarantee a stable brightness condition during measurement.
* The attenuation decreases with increasing temperature when PIN diodes are biased by a very high voltage source and high value of bias resistor (equivalent to constant current source
R1208 was used as part of the constant current source
, described below in the volt reference paragraph.
To evaluate resistance changes is thermistor involved in the measuring bridge powered constant current source
. The tension on the bridge Ub corresponds to the thermistor resistance (1)
In contrast, LED lamp loads (Figure 2) can vary greatly across different manufacturers and designs, but most can be characterized by a diode-capacitor power supply feeding a constant current source
. The diodes rectify the applied AC voltage, allowing it to charge the storage capacitor, while the LED elements draw a constant current from the power supply related to the desired dimming level and brightness.
The basic requirement of an internally compensating sensor is a constant current source
If the load resistance is small, the cell operates in the region AB of the curve, where the cell behaves as a constant current source
, almost equal to the short-circuit current.
A simplified CTMU block diagram is shown in Figure 2 and consists of a constant current source
and high-speed switch, an ADC, a discharge switch, and an analog multiplexer.