DIODE LOGIC GATES (OR Gate) Y=A+B+C

DIODE LOGIC GATES (OR Gate) Find V and I.

DIODE LOGIC GATES (OR Gate) D1 is ON D2 and D3 are off. Therefore, V=3V Also I=(3-0)/1k=3mA

DIODE LOGIC GATES (AND Gate) Y=A.B.C

DIODE LOGIC GATES (AND Gate) Find V and I.

DIODE LOGIC GATES (AND Gate) D1 and D2 are off. D3 is ON. Therefore V=+1V Also I=(5-1)/1k=4mA.

VOLTAGE MULTIPLIERS Voltage multipliers are circuits that provide a dc output which is multiple of the peak input voltage. For example, a voltage doubler provides a dc output voltage that is twice the peak input voltage, and so on.

VOLTAGE MULTIPLIERS While voltage multipliers provide an output voltage that is much greater than the peak input voltage , they are not power generators. When a voltage multiplier increases the peak input voltage by a given factor, the current is decreased by approximately the same factor.

VOLTAGE MULTIPLIERS Because of this, voltage multipliers are usually used in low current high voltage applications. (As in cathode ray tube in a television).

HALF WAVE VOLTAGE DOUBLER During the first half cycle point x is positive with respect to point y of the input. A charging current will be forced through capacitor C1 and diode D1 which will be forward biased. Capacitor C1 will charge to the peak for the time T/4. During the same time D2 will remain off.

HALF WAVE VOLTAGE DOUBLER During the negative half cycle of the input point x will be negative with respect to y and voltage of C1 (Vc1 and Vin) are series additive. A current will try to follow from y to x but D1 does not allow as it is off. However D2 will be conducting.

HALF WAVE VOLTAGE DOUBLER This permits C2 to charge up due to the current Ich2 will follows from point y through C2 through D2 and back to point x. Voltage on C2 will be of magnitude 2Vm. Applying KVL we can write –Vc1 - Vin = Vo but

HALF WAVE VOLTAGE DOUBLER Vc1 = Vmax Hence V0 = -2V Output waveform will be like this

Dual Power Supply

ZENER DIODE

ZENER DIODE In case of zener diode the differential voltage and current in the zener region of the characteristic curve is given by ΔV = rz. ΔI Where rz = inverse of the slope or incremental resistance of zener diode at operating point.

ZENER DIODE The almost linear i-v chracteristic of zener diode suggests that the device can be modeled as shown

ZENER DIODE In practice, values of knee voltage and Vz0 are considered same. From the model Vz =Vzo +rz + Iz When Iz > Izk & Vz > Vzo

ZENER DIODE SHUNT REGULATOR A regulator must posses two properties No change in V0 .with any change in Vs . No change in Vo with any change in IL. Therefore two parameters are related as

ZENER DIODE SHUNT REGULATOR line regulation = ΔVo/ ΔVs Load regulation = ΔV0/ ΔIL Another method to describe these regulation

ZENER DIODE SHUNT REGULATOR