The working principle of voltage stabilization of series regulated power supply
Assume that the output voltage UO decreases for some reason, that is, the emitter voltage (UT1) E of T1 decreases. Since UD1 remains unchanged, the emitter junction voltage (UT1) BE of T1 increases, causing the base current (IT1) B of T1 rises, causing the T1 emitter current (IT1) E to be amplified β times and rise. From the load characteristics of the transistor, it can be seen that at this time T1 conducts more fully and the tube voltage drop (UT1) CE will decrease rapidly, and the input voltage UI will become more Added to the load, UO rebounded quickly. This adjustment process can be represented by the following change relationship diagram:
UO↓→(UT1)E↓→UD1 constant→(UT1)BE↑→(IT1)B↑→(IT1)E↑→(UT1)CE↓→UO↑
When the output voltage rises, the entire analysis process is opposite to the change in the above process. We will not repeat it here, but simply express it with the following change relationship diagram:
UO↑→(UT1)E↑→UD1 constant→(UT1)BE↓→(IT1)B↓→(IT1)E↓→(UT1)CE↑→UO↓
Here we only analyze the working principle of voltage stabilization when the output voltage UO is reduced. In fact, the working principle of voltage stabilization when the input voltage UI is reduced is similar to this. In the end, it is reflected in the reduction of the output voltage UO, so the working principle is roughly same.
It can be seen from the working principle of the circuit that there are two keys to voltage stabilization: first, the voltage stabilization value UD1 of the voltage regulator tube D1 must remain stable; second, the adjustment tube T1 must work in the amplification zone and have good working characteristics.
Precautions when using DC regulated power supply
1. To prevent magnetic leakage interference, the distance between the voltage regulator and the equipment used should not be less than 2 meters. Various magnetic records, disks, cards, etc. should be kept 2 meters away from the machine to prevent accidental magnetization.
2. The voltage stabilizer generally includes input terminals (A, B, C), output terminals (a, b, c, n), shielding, and core shell grounding terminals. These terminals have been correctly connected in the voltage stabilizing system.
3. If the load unbalance exceeds 20%, connect a resistive load in parallel to one phase of the light load to balance it. Similarly, if the unbalance of the line voltage at the input end exceeds 10%, it will also affect the voltage stabilization performance of the machine. , at this time, a single-phase voltage regulator should also be installed at the input end to ensure that the line voltage at the input end is basically balanced. The balance between the input voltage and load does not exceed the above range, and the output line voltage imbalance is ≤5%.
4. When there is a short circuit in the load equipment, the user needs to shut down the machine for inspection and then turn it on again after eliminating the short circuit fault.
5. When the continuous working time is long, the machine will have a certain temperature rise, and its indicated value will drop slightly, slightly lower than the actual voltage value.
6. It should be placed in a location with good ventilation. If the ventilation conditions are poor, please install a ventilation fan indoors.
