To build a controlled rectifier or a phase controlled rectifier, the diodes in the rectifier circuits are replaced by SCRs.
The mobile radio channel places fundamental limitations on the performance of wireless communication systems.
The wireless transmission path may be of two types:
This circuit can be primarily used for charging 12V Ni-Cd battery packs. Any way 6V and 9V battery packs can be also charged by using this circuit a little compromise on power efficiency.
A power diode must be protected against over-voltage, over-current and transients.
An ideal switch is shown in Figure 1. The power loss generated in the switch is the product of the current through the switch and the voltage across the switch.
Diodes in DC Circuits
To analyze diode circuits, the state of the diode (on or off) must first be found. The diode can then be replaced by the switch equivalent circuit.
Peak Inverse Voltage (PIV)
The peak inverse voltage rating of a diode is the maximum reverse voltage that can be connected across a diode without breakdown.
The maximum power that can be controlled by a single diode is determined by its rated reverse voltage and by its rated forward current.
If the load current is greater than the current rating of a single diode, then two or more diodes can be connected in parallel (see Figure 1) to achieve a higher forward current rating.
To obtain satisfactory and reliable SCR operation, it is necessary to provide protection against over voltages and over currents.
For proper operation of circuits using SCRs, the trigger circuits should supply the firing signal at precisely the correct time to assure turn-on when required.
If an SCR is forward-biased and a gate signal is applied, the device turns on. However, once the anode current IA is above the holding current, the gate loses control.