Question

+12V 25 miles +5V GND Ul 25 miles C4 0.luF 100uF 0.luF 100uF GND GND GND GND GND +5V T3 12V DC T4 +12V DC T6 +5V DC i)2 miles 40 miles 40 milesi 330R 25 miles IR 1R D4 D5 ALED-RED +5V IGND NS819 INS819 GND

Explain how D4, D5, R4 and R5 provide protections to the circuit.

Your answer does not to be very complex just some simple concepts will be fine.

Answer 1

First let us explain the role of D4 and D5 here. usually this combination uses maximum current as due to reverse bias current from D5 cannot be gnd and this combination can be utilized to protect integrated circuits and transistors from the brief high voltage generated. Both diodes also help to protect circuit from reverse polarity.

Now let us discuss about R4 and R5, wherein these resistors are used in this circuit as a bleeder resistor. In electronics, a bleeder resistor is a resistor connected in parallel with the output of a high-voltage power supply circuit for the purpose of discharging the electric charge stored in the power supply's filter capacitors when the equipment is turned off, for safety reasons.