Schematic Rise

This is a Variable 5 to 20V DC Supply Circuit Diagram. If you are looking for a low drop voltage regulator that can provide a power supply of 1A with an output voltage of between 5V and 20V DC, National Semiconductor LM2941 Low Dropout Adjustable Regulator is that you can pick to make use of. Its a typical dropout voltage of 0.5V which means that the input supply need only must be 0.5V DC over the desired output voltage. 

 

Its other features include internal short schema current limit and reverse battery protection. As shown in the schematic below, the regulator has five pins which consists of the ON/OFF control, Input Voltage, Output Voltage, Ground & Adjustable pins. ON/OFF is used for the purpose of switching on & off of the regulator. The capacitors C1 & E1 are to be placed as close as feasible to the regulator. 

The output of the schema can be varied by varying the worth of potentiometer VR1 from 5V DC to 20V DC. The input voltage is limited from five.5V DC to 30V DC. Resistor R1 must be greater than 1K. The worth of the VR1 that needs to be set is calculated from the formula given below: 

VR1 = R1[(Vout/1.275) - 1] ohm

 If R1=1K, Vout = 5V, VR1 should be set to 2.9K ohm. 

 If R1=1K, Vout = 20V, VR1 should be set to 14.7K ohm

How to Build a Bipolar Power supply for Battery instruments. A bipolar power supply overcomes those limitations. Most importantly, it can provide both positive and negative voltages from a single pair of terminals. There are no relays to switch polarity, so a bipolar supply can move smoothly from positive, through zero, to negative voltages. 

It also regulates zero volts or other very small voltages. In this Bipolar Power supply for Battery instruments schema diagram to generate regulated ± 5-V supplies from a pair of dry batteries, the schema of Fig. 1 is commonly used. In order to give protection from inadvertent reverse connection of a battery, a diode in series with each battery would produce an unacceptable voltage drop. 

The more effective approach is to fit diodes Dl and D2 as shown in Fig. 2, in parallel with each battery. When the supply is switched off, there is the risk of a reverse bias being applied across the regulators, if there is significant inductance or capacitance in the load schema. Diodes across the regulators prevent damage. When the power supply is switched on, the two switches do not act in unison. 

There is a probability that one or the other regulators will be latched hard off by the other. To prevent this, D3 and D4 are Zener diodes so that ± 5-V rails are pulled up by the batteries until the regulators establish the correct levels.

This FM transmitter schema can be used as a wireless microphone,  can be received by an ordinary 88- to 108-MHz FM broadcast receiver. For the power supply, this transmitter schema is powered by a 9 V battery. To comply with the radiation limit of FCC rules, keep the antenna length under 12 inches. L1 is 6 turns of #24 wire wound around a pencil or a 1/4″ form, with turns spacing of 1 wire diameter. C6 is a gimmick capacitor which has value about 1 pF.

Build a 3 Watt Stereo Amplifier Circuit Diagram. This schema using MAX 7910 IC. The MAX9710 a stereo audio power amplifier IC capable of delivering 3Watts of out put to 4 Ohm loads. MAX9710 can be operated from a single 4.5V to 5.5V power supply , makes it ideal for hand held applications.The IC for 

3 Watt stereo amplifier schema also features thermal overload protection.

 This 3 Watt stereo amplifier schema is suitable for small power audio devices such as radio sets and portable CD players. 5 V DC power supply is used for powering the 3 Watt stereo amplifier schema. 6V battery with an IN 4007 diode series to the positive terminal of it can also be used instead of 5 V DC supply. The 3 Watt stereo amplifier schema will get a supply voltage approximately 5 V after 0.7 V voltage drop across diode.

 

This is a simple High voltage inverter schema diagram. This inverter schema works with a transistor and transformer and other components to increase the voltage becomes high. Input supply voltage ranging from 3V to 6V DC, later it was raised to high voltage AC. However, in this inverter schema output current is very small, probably under 0.1A even smaller. However, its use you can apply it on a fluorescent lamp 10W maximum power only, and that too takes time to switch on fluorescent lamps.

 High voltage inverter schema diagram



Part List
R1 = 4K7
R2 = 2K2
R3 = 330K
C1 = 100nF
C2 = 100nF 275V
C3 = 0.22uF 275V
Q1 = D506
L1 = 100 times winding, with 0.8mm diameter copper wire
L2 = 50 times winding, with 0.8mm diameter copper wire
L3 = 5000 times winding, with 0.4mm diameter copper wire

Varying Brightness AC Lamp Circuit, an SCR is used to slowly vary the intensity of a 120 volt light bulb by controlling the time that the AC line voltage is applied to the lamp during each half cycle.

Varying Brightness AC Lamp Circuit Diagram


Caution:
The schema is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the schema while it is connected to the AC power line. A 2K, 10 watt power resistor is used to drop the line voltage down to 9 volts DC. This resistor will dissipate about 7 watts and needs some ventilation.

Operation:
A couple NPN transistors are used to detect the beginning of each half cycle and trigger a delay timer which in turn triggers the SCR at the end of the delay time. The delay time is established by a current source which is controlled by a 4017 decade counter. The first count (pin 3) sets the current to a minimum which corresponds to about 7 milliseconds of delay, or most of the half cycle time so that the lamp is almost off. Full brightness is obtained on the sixth count (pin 1) which is not connected so that the current will be maximum and provide a minimum delay and trigger the SCR near the beginning of the cycle. The remaining 8 counts increment the brightness 4 steps up and 4 steps down between maximum and minimum. Each step up or down provides about twice or half the power, so that the intensity appears to change linearly. The brightness of each step can be adjusted with the 4 resistors (4.3K, 4.7K, 5.6K, 7.5K) connected to the counter outputs.

The schema has been built by Don Warkentien (WODEW) who suggsted adding a small 47uF capacitor from ground to the junction of the current source transistor (PNP) to reduce the digital stepping effect so the lamp will brighten and fade in a smoother fashion. The value of this capacitor will depend on the 4017 counting rate, a faster rate would require a smaller capacitor.

This is a Simple 90Vrms Voltage Regulator Circuits Diagram. The 90Vrms Voltage Regulator Circuits Diagram is an open loop rms voltage regulator that will provide 500 watts of power at 90 V rms with good regulation for an input voltage range of 110-130 V rms. With the input voltage applied, capacitor Cl charges until the firing point of Q3 is reached causing it to fire. 

This turns Q5 on which allows current to flow through the load. As the input voltage increases, the voltage across R10 increases which increases the firing point of Q3. This delays the firing of Q3 because Cl now has to charge to a higher voltage before the peak-point voltage is reached.Thus the output voltage is held fairly constant by delaying the firing of Q5 as the input voltage increases. For a decrease in the input voltage, the reverse occurs.