Showing posts with label power supply. Show all posts
Showing posts with label power supply. Show all posts
This is a basic circuit of a step up DC-DC converter which the output voltage is more than the
input, the circuit could be used to power a 9v or more devices from a 6v or even a 1.5v battery, charge batteries (3-12v) with 1.5v solar cell...
The circuit uses an oscillator using Schmitt trigger, all types of oscillators works, one transistor (Ex: BD139 or similar), resistors, coil (many different
types of coils work even a small DC motor works! or you can wind 60 turn on ferrite)
R1 and C1 determine the oscillation frequency, different types of coils perform differently at frequencies changes.
I used 5v input and toroid ferrite, the output exceed 60v (no load). The output voltage will drop as the load go higher.
Other types of oscillators can be used:
Other one to use see here: Simple rectangular oscillator
7812 or 7805 regulators can be used to stabilize the output voltage. (remember not to exceed the maximum input voltage)
Thanks
Joule thief is a simple step up converter, that converts DC to DC, for example you can drive a 3.4V Led with single 1.2V battery, even if the battery is almost dead. It extract all the energy stored in batteries.
You need:
- 1Kohm resistor.
- small NPN transistor ( for example 2N3904 ).
- ferrite toroid, (can be found on power supplies, radio), and wire to wrap around the toroid, ( big toroid and more turns = more output power and voltage you get ) the method of wiring is shown under, (if you don't have the toroid try the other methods under).
- and Led or anything you can't drive with one battery like: leds, lighting a neon lamp, charging capacitors with high voltage, charging other batteries Ex: charging 3.6V batteries with 1.2V battery...
you can change the 1.2V battery with 9V to get high voltage output that can drive neon lamps...
you can charge batteries...
A demostration:
A different types of coils can be used
Thanks
This is a low current transformerless power supply for small applications. The capacitor C1 reduces the high volt AC. D1-D4 rectifies
AC to DC and C2 reduces ripples. R1 discharge stored energy in C1 to avoid electric shock when power is off. R2 limits inrush current. The Zener diode is used to get regulated DC output.
-The Zener value can be changed to get other output voltages.
If you don't have a zener diode use normal diodes in series for
exemple 3 diodes in series give 1.8v-2.2v depending on the load
current.
- The value of the capacitor determines the maximum output current, now let's calculat'it it's easy...:
- First we calculate the impedance of the circuit (C1 and R2): Zc+R2 = (1/(2*pi*F*c))+R2 = (1/(314*0.0000022))+100 = 1547Ω.
- Second we calculate the voltage across C1 and R2: V-Vz-Vd = 230-12-1.4 =216V. (( V (main AC) Vz (Zener voltage) Vd (voltage drop across diode brige 1.4v) )).
- Third the max current: 216/1547 = 140 mA.
Use the same calculations for other values.
Ask if you have any questions.
Thanks.
