Ad
related to: datasheet of zener diode in parallel line analysis system
Search results
Results from the WOW.Com Content Network
It is also worth noting that the temperature coefficient of a 4.7 V Zener diode is close to that of the emitter-base junction of a silicon transistor at around −2 mV/°C, so in a simple regulating circuit where the 4.7 V diode sets the voltage at the base of an NPN transistor (i.e. their coefficients are acting in parallel), the emitter will ...
Reference voltage vs free-air temperature at test conditions. Design-center (middle plot) and worst-case deviation of ±2% (upper and lower plots) [12] The nominal reference voltage, V REF =2.495 V, stated in a datasheet, is tested in zener mode at an ambient temperature of +25 °C (77 °F), and I CA =10 mA. [13]
Here, the load current I R2 is supplied by the transistor whose base is now connected to the Zener diode. Thus the transistor's base current (I B) forms the load current for the Zener diode and is much smaller than the current through R 2. This regulator is classified as "series" because the regulating element, viz., the transistor, appears in ...
The Shockley diode equation relates the diode current of a p-n junction diode to the diode voltage .This relationship is the diode I-V characteristic: = (), where is the saturation current or scale current of the diode (the magnitude of the current that flows for negative in excess of a few , typically 10 −12 A).
Since the forward voltage of a diode is small, this kind of voltage regulator is only suitable for low voltage regulated output. When higher voltage output is needed, a zener diode or series of zener diodes may be employed. Zener diode regulators make use of the zener diode's fixed reverse voltage, which can be quite large.
A voltmeter is then connected in parallel to the resistors and the measured values of voltage for each load state can be used to calculate the load regulation as given in the equation above. Programmable loads are typically used to automate the measurement of load regulation.
In most cases, this can be easily filtered out by placing a small capacitor in parallel with the VR tube or using an RC decoupling network downstream of the VR tube. Too large a capacitance (>0.1 μF for an 0D3, for instance), however, and the circuit will form a relaxation oscillator , definitely ruining the voltage regulation and possibly ...
The transfer characteristic has exactly the same shape of the previous basic configuration, and the threshold values are the same as well. On the other hand, in the previous case, the output voltage was depending on the power supply, while now it is defined by the Zener diodes (which could also be replaced with a single double-anode Zener diode).
Ad
related to: datasheet of zener diode in parallel line analysis system