If you select Start > Settings > Personalization > Taskbar and turn on the Power toggle, but the battery icon does not appear on the taskbar, in the search box on the taskbar, type task manager, and then select Task Manager in the list of results. On the Processes tab under Name, right-click Explorer, and then select Restart. Wait a few seconds, and then right-click the battery and select Enable. Under Batteries, right-click the battery for your device, select Disable, and select Yes. On a device that uses battery power, if you select Start > Settings > Personalization > Taskbar and the Power toggle is greyed out or not visible, in the search box on the taskbar, type device manager, and then select Device Manager in the list of results. ( Note: The Power toggle is not visible on a system such as a desktop PC that doesn't use battery power.) If you still don't see the battery icon, select Show hidden icons on the taskbar, and then select the battery icon. Choose Select which icons appear on the taskbar, and then turn on the Power toggle. Select Start > Settings > Personalization > Taskbar, and then scroll down to the notification area. Connecting a 33K resistor across D9 corrected this little problem without affecting anything else.To check the status of your battery, select the battery icon in the taskbar. This was traced to Zener D9 dropping out of conduction thus starving the voltage divider. Testing on variable voltage turned up an interesting bug –when the voltage was turned down to about 10V, all LEDs lit again. 0:00 / 17:08 12v Battery Voltage Monitor using LEDs and LM339 Voltage comparator Electronic Clinic 60.3K subscribers Subscribe 9.5K views 4 years ago USA Download Simulation: Upgrading. To reduce standby power, a push-to-test pushbutton may be used. Great Accuracy: Comes with high accuracy. This current can be adjusted simply by varying the emitter driver resistors (R9 through R13). Battery Tester: The battery capacity indicator module can read the approximate battery level in the current situation. The LEDs are biased to operate at 2.3mA which is reasonably bright for high efficiency LEDs. The remaining LEDs will switch on close to the indicated voltage –accuracy of those voltages may suffer slightly, but should be close. Then adjust the calibration pot until D2 flickers. The quad comparator compares the various voltages from the two dividers.įor calibration, connect to a voltage source that can be set to the highest LED threshold (41V in this case). R7 & 8 form a voltage divider to that divides the battery voltage by a factor of 9. Tied to this is a string of divider resistors (R2-6) that set the various fixed voltage levels. While this is relatively busy, it places virtually no burden on the shunt regulator.ĭ1 is the voltage reference zener. By limiting the emitter current, the LED current is automatically limited to the same value. However, the cascode transistors may drive LEDs that are tied to a much higher voltage –up to 80V using the MPS-A16. By tying the bases of these transistors to the 13V bus, the LM339 open collector drive transistors never see more than 13V. In this circuit it offers one great property –low voltage in, high voltage out. This configuration is generally used for RF amplifiers. For voltage indication, LEDs can be connected to the IC. So, the IC is designed to indicate four voltage levels respective to a common voltage reference. There are two solutions for this: increase the current rating of the shunt regulator so that it can power the LEDs, or run the LEDs via a cascode amplifier arrangement –I chose the cascode amplifier.Ī cascode amplifier is a configuration where one transistor feeds a 2nd transistor that is connected in the common base configuration. LM339 is a single supply quad comparator which has four channels to detect the magnitude of analog voltages and indicate the voltage level by lighting up to 4 LEDs. However, the LM339 open collector outputs cannot drive LEDs powered from the battery bus due to the same maximum voltage limitation. 1.73K subscribers Subscribe 27K views 8 years ago Proteus This is a Battery Monitor Circuit. Shunt regulators are very simple, inexpensive and robust –good for this application. The solution involves running the IC power rail off a zener shunt regulator. One limiting factor is the LM339 that has an absolute maximum voltage rating of 36V –and it is not good practice to operate near that point.
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