Skema Rangkaian|Electronic Schematic Circuit Diagram

High Output Power RF Push-Pull MOSFET Oscillator

Sat, 06 Mar 2010 10:58:30 +0000

With the circuit shown here you can create high frequency electromagnetic waves with very high output power.

Possible applications are experiments with wireless power transmission, RFID Transponder, tesla coils and the like.

Dependent on the coil, capacitor and cooling of the transistors output power in the range of 20W and more can be obtained.

At short distances, other electronic circuits may be disturbed or even destroyed. Broadcasting, RFID, AntiTheft, Wlan, medical appliances (pacemakers!) can be disturbed in a large area!

Never operate this circuit without taking precautions !

It may be illegal to operate in your Country!

The Circuit:

It is a standard Push Pull Oscillator, based on Power Mosfet Transistors.

The PCB provides mounting space for two SK104 heatsinks, this allows for remarkable output power for such a small device.

For a high resolution layout, click on the Image!

Component Values:

Operation Voltage is about 15V DC

If you wish to use smaller operating voltages, you must increase R2 and R3. Oscillation starts when the voltage drop across R2 resp. R3 reaches the MOSFET’s thresold Voltage, approx. 4..6V

Mosfet: IRF510

R1, R4 100k

R2, R3 27K

C4, C5 100u

C1 choose for your desired frequency

C2,C3 ca 10% of C1

D1,D2 15V Z-Diodes

A PushPull Oscillator requires a coil with a Center Tap. For my tests i used 12 Turn 1mm insulated Copper Wire, ca 40mm Diameter.

The Center Tap is connected to PAD1

A Frequency Range from 200kHz to 10MHz was generated using this coil.

The Resonance Frequency of the is calculated by (approx)

Important!

The Capacitors, especially C1 should be low ESR, otherwise they will heat up and be destroyed!

A LED connected to a small receiver coil lit up at about 20cm distance. At 10 cm, it became hot and was destroyed eventually!

Taken From : Solderingpoint.com

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78XX Family Regulators Universal PCB for PSU

Sat, 06 Mar 2010 10:55:01 +0000

Many DIY projects require a small Power Supply.

The 78XX family is ideally suited for this job, and with this little PCB you can easily build small Power Supplies for virtually every application.

The circuit is very simple:

The Alternating current is applied to X1 and rectifies by B1.

It charges a large Capacitor C1 to power the regulator.

The output voltage depends on the Regulator you use, e.g. 7805, 7812,7815…

Dimensionierung:

C1:4700u, with sufficient voltage Rating!

C2:0.33u

C3:0.1u

The Heatsink should be enough for devices with moderate power consumption.

78XX Family Regulators Universal PCB for PSU Circuit

Board size ca 70*50 mm.

High Resolution Layout can be found here.

78xx circuit diagram, 78XX pcb

Tube Amplifier With EL 84/6BQ5

Sat, 06 Mar 2010 10:49:08 +0000

When experimenting with tube amplifiers, you ability be abashed about the altered modes of operation, like triode or pentode mode. To accord a little advice i developed this PCB. You can body baby Amplifiers based on 6P14/6BQ5/EL84 easily, and the achievement Power of 2..6 Watts is added than abundant for home use.

With this PCB you can try out the altered Modes by agency of Jumper Wires.

The Schematic is actual simple:

Tube Amplifier With EL 84/6BQ5 Schematic

This PCB is of course only one part of an Amplifier, you will need at least a Power Supply and output Transformers.

The PSU has to supply the filament Voltage and the Plate Voltage of about 250V

A suitable PSU can be found here..

Layout and compomnent place. High resolotion Layout can be found here here.

Filament voltage is connected to X2, Plate Voltage is connected to X3 and the output transformer is connected to X4

A Pentode like the EL84 can be operated in 3 different Modes:

Ultralinear
Triode
Pentode

Each of the 3 Modes has its unique sound characteristics, just try them and find out which one you like best!

An Overview how to connect the different modes

Pentode Mode	Screen Grid connected to Plate VoltageJ1 in place, J2 not in Place output Transformer connected to X4/1 and X4/3	Ua=Ug2=250V Output transformer 5.2kOhm Cathode Resistor 135Ohm Idle Current 48mA
Pentode Mode, sepeated screen Grid Voltage	J1 not in place,J2 not in place output transformer connected to X4/1 und X4/3, Ug2 to X4/2	Output transformer 5.2kOhm Cathode Resistor 135Ohm Idle Current 48mA
Ultralinear	Screen Grid connected to UL Tap of output TransformerJ1 not in place, J2 not in place Output transformer connected to X4/1 and X4/3, UL TAP to X4/2	UL Output transformer needed
Triode	Screen Grid connected to AnodeJ1 not in place, J2 in Place Output transformer connected to X4/1 and X4/3	Ua=250VOutput transformer 3.5kOhm Cathode Resistor 270Ohm Idle Current 34mA

Component Values

R1 Cathode Resistor, see table above

R2 1kOhm

R3 1MOhm

R4 100Ohm/1W

C1 470uF/35V

Selecting a Tube:

All EL84 Types can be used, such as 6P14 or 6BQ5. The circuit was tested with EL84.

Bestückungshinweise:

The Cathode Resistors and the screen Grid Resistor should be rated for 1W, as the can get quite warm during operation.

The tube gets very hot during operation, so ensure proper venting!

An EL84 type tube needs several volts for full output power. Usage of a preamp is therefore recommended. A CD Player with headphone-out is a good start and usually enough to drive the Tube. the output needs to be DC-Free, so decoupling with a suitable capacitor might be neccessary.

Never connect a signal source with a DC Component to the circuit, this could lead to damage of the Tube and output transformer

Always ensure that a proper load is connected to the output transformer! Tube Amplifiers usually dont like being operated without load!

Here a picture of a complete AMP, consisting of PSU, power transformer, output Transformer and EL84 PCB

Via : solderingpoint.com

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