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Showing posts from August, 2011

Offline Switching Power Supply Circuit (5V - 10A / 50W)

The following diagram is the circuit diagram of offline switching power supply circuit:

Circuit Diagram:

Parts List:

This switching power supply is using a MOSFET. For 220V AC voltage input, use BUZ80A/IXTP4N8 MOSFET. And for 110V AC input voltage, use GE IRF823 MOSFET. The output will be 5 Volt DC with electric current can be reach 10A.

Positive Regulator Circuit with PNP and NPN Transistor Boost

Here the schematic diagram of positive regulator with PNP and NPN transistor boost. Inside the circuit, Q1 and Q2 are wired in the classic SCR or thyristor configuration. In which higher input voltages or minimum element count are needed, the circuit for thyristor boost could be applied. The thyristor is working in a linear mode with its cathode as the control terminal and its gate to be the output terminal. This is known to be the remote base configuration.

5V to Isolated 5V Converter Circuit

This is the circuit diagram of 5V to Isolated 5V Converter, rated at 20mA electric current.

In this converter circuit, a negative output voltage dc to dc converter generates a -5V output at pin A. In order to generate -5V at point A. the primary of the transformer must fly back to a diode drop more negative than -5V. If the transformer has a tightly coupled I : 1 turns ratio. there will be a 5 V plus a diode drop across the secondary. The IN5817 rectifies this secondary voltage to generate an isolated 5V output. The isolated output is not fully regulated since only the -5V at point A is sensed by the MAX635.

5V Regulated Power Supply Circuit with Over Voltage Protection

The 5V regulated power supply for TTL and 74LS series integrated circuits, has to be really precise and tolerant of voltage transients. These IC's are effortlessly damaged by short voltage spikes. A fuse will blow when its electric current rating is exceeded, but demands several hundred milliseconds to respond. This circuit will react in several microseconds, triggered when the output voltage exceeds the limit of the zener diode.

This circuit uses the crowbar method, where a thyristor is employed and short circuits the supply, causing the fuse to blow. This will take position in a few microseconds or less, and so provides considerably higher protection than an ordinary fuse. If the output voltage exceed 5.6Volt, then the zener diode will conduct, switching on the thyristor (all in some microseconds), the output voltage is therefore reduced to 0 volts and sensitive logic IC's will probably be saved. The fuse will nonetheless take just a few hundred milliseconds to blow but this…

Voltage Regulator with FET KP103K

This is a voltage regulator circuit built based FET KP103K. The FET VT3 acts as a dynamic load for the transistor VT2. Because of this factor increases the voltage regulation: when the input voltage from 11 to 19 V output voltage varies within ± 60 mV. Rated output voltage using Zener type D814B is 9 V.

Voltage Regulator with FET KP103K circuit source: Voltage Regulator with FET