RC filter circuit b

On some occasions. If the load current is not large, in order to reduce weight, cost and size,
the L on the above two compound filters can be replaced with a resistor to form an RC type filter and an RC-7r type filter, as shown in the figure. Show.
    In the RC filter , a large R has a good filtering effect, but the voltage drop loss on the resistor is also large. Generally, in the case of small current, the resistor is usually tens
to hundreds of ohms, and the capacitor is several hundred microfarads (200yF, 5001uF).
    After rectification, a filter capacitor needs to be added. The capacity of the filter capacitor needs to be selected according to the size of the electrical load, usually from tens of microfarads to hundreds of microfarads
. Some DC power supplies with higher requirements also need to add an integrated voltage regulator for voltage stabilization to obtain a high-quality regulated power supply with smaller ripples.
The relationship between filter capacitor capacity and load current is shown in Table 12-2. The size of the filter capacitor can be selected according to the output current .