Note:
Since the large capacitors are single polarity the importance of connecting them is a priority. Not connecting them properly will cause an explosion.
INTRODUCTION:
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Equipment |
Description |
|
O Scope |
100 MHz oscilloscope |
|
Components |
Transformer, Full Rectifier, op-amp 741 7805,TIP 2027,TIP 3055, Zener, Caps, Resistors. |
|
DMM |
|
DESCRIPTION:
· Input: Once the plug is connected to the outlet, the AC electricity flows to the step down transformer. The secondary is centered tap so it can provide a positive and negative potential to the system. The AC is then rectified and filtered, smoothes the full rectified signal, before entering the regulators.
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|
Note: Since the large capacitors are single polarity the importance of connecting them is a priority. Not connecting them properly will cause an explosion. |
·
Positive Power Supply: The Positive Power supply has a 5 Voltage regulator which
provides 5 volts to the TTL components and the maximum current is 1 A. The other
half of the circuit is the positive voltage supply. The op amp acts as a
comparator and controls the base of the NPN transistor. The reference voltage is on the
positive side of the op-amp and the sensing voltage is the potentiometer, which
is on the negative side of the op-amp. The reference resistor value depends on
the rms input and the operating current of the zener diode. (rms
The Ic is the current of the zener diode and the rms is the value of the
reference input.
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Note: The output capacitor is to provide an easy path for ac signals. If you are powering an audio device then a high value double polarity capacitor is need. |
·
Negative Power Supply: The second half the circuit is the
negative side, which provides the negative potential to power dual potential
devices. The op amp acts as a
comparator and controls the base of the PNP transistor. The reference is on the
positive side of the op-amp and the sensing voltage is the potentiometer, which
is on the negative side of the op-amp. The reference resistor value depends on
the rms input and the operating current of the zener diode. (-5 - rms
The Ic is the current of the zener diode and the rms is the value of the
reference input.
|
|
Note: The negative power supply is the mirror image of the positive power supply. If you are powering an audio device or any signal depended device which then a high value double polarity capacitor is need. |
