Skip to main content

Transformer Less Power Supply Circuit Diagram


This clever design uses 4 diodes in a bridge to produce a fixed voltage power supply capable of supplying 35mA. All diodes (every type of diode) are zener diodes. They all break down at a particular voltage. The fact is, a power diode breaks down at 100v or 400v and its zener characteristic is not useful.  But if we put 2 zener diodes in a bridge with two ordinary power diodes, the bridge will break-down at the voltage of the zener. This is what we have done. If we use 18v zeners, the output will be 17v4.
When the incoming voltage is positive at the top, the left zener provides 18v limit (and the left power-diode produces a drop of 0.6v).  This allows the right zener to pass current just like a normal diode but the voltage available to it is just 18v.  The output of the right zener is 17v4. The same with the other half-cycle.  The current is limited by the value of the X2 capacitor and this is 7mA for each 100n when in full-wave (as per thiscircuit). We have 10 x 100n = 1u capacitance. Theoretically the circuit will supply 70mA but we found it will only deliver 35mA before the output drops. The capacitor should comply with X1 or X2 class. The 10R is a safety-fuse resistor.
Circuit diagram:
TransformerLess Power-Supply-Circuit-Diagram
TransformerLess Power Supply Circuit Diagram 
The problem with this power supply is the "live" nature of the negative rail. When the power supply is connected as shown, the negative rail is 0.7v above neutral. If the mains is reversed, the negative rail is 340v (peak) above neutral and this will kill you as the current will flow through the diode and be lethal. You need to touch the negative rail (or the positive rail) and any earthed device such as a toaster to get killed. The only solution is the project being powered must be totally enclosed in a box with no outputs. 

Comments

Popular posts from this blog

Transceiver Homebrew QRP SSB 80M Band

Radio communication transceiver is a radio transmitter at the same time the plane doubles as a radio receiver used for communication purposes. It consists of the transmitter and the receiver are assembled in an integrated way. In mulamula generation, the transmitter or receiver or transmitter and receiver sections are assembled separately and is part of a stand sendirisendiri and can work well sendirisendiri Currently employed both parts are integrated in turn. Aircraft simple transmitter consists of an oscillator generating radio vibration and this vibration after vibration boarded with our voice, in a technique called dimodulir radio, then by the antenna is converted into radio waves and transmitted. As we know that the sound waves we can not reach long distances, although its power is quite large, while the radio waves with a relatively small force can reach a distance of thousands of kilometers. In order for our voice can reach a far distance, then our voice superimposed on radio w...

NE566 Function Generator Circuit Diagram

The NE566 Function Generator is a Voltage-Controlled Oscillator of exceptional linearity with buf fered square wave and triangle wave outputs. The frequency of oscillation is determined by an external resistor and capacitor and the voltage applied to the control terminal. The Oscillator CAN be programmed over a ten-to-one frequency range by proper selection of an external resistance and modulated over a ten-to-one range by the control voltage, with exceptional linearity.  FMAX = 1 MHz     WIDE 1000:1 Continuous Sweep Possible  NE566 Function Generator Circuit Diagram Pdf Datasheet  Sourced by : Circuitsstream

TDA2030 complete tone control

At this time I present a series of amplifiers that use IC TDA2030, but this series is equipped with a tone control. Tone controls include Bass, Treebel, and Volume. Power amplifier and tone control has been put together in a single PCB. As well as its power supply circuit was also used as one with the power amp, and tone control. Making it easier in the installation and will look neat. Schematics Layout PCB PCB design This amplifier is a mono amplifier type, can be modif for guitar amplifiers. If not coupled amplifier (mic preamp) then you must deactivated potensio treble and bass, why? because if not using a mic preamp and still maintain potensio treble and bass sound input (input) from the guitar will not or the maximum discharge is not tight on the speakers. So you must deactivated a way to decide which directly connected capacitor with the tone control circuit, and capacitor were connected directly to potensio volume and input jack.