Small DC to DC converter 1.5V or 3V to 9V by TL496

When you have sized batteries is 1.5V or 3V, but need a voltage 9VDC, DC converter circuit to help you for sure!
Some problems in the electronics job, can modify or bring devices come to apply available not difficult If we know the principles and limitations of those devices. As the project is being offered at this time, will be bringing sized batteries 1.5 volt connected through an electronic circuit called dc converter to increase the voltage to have higher value be 9 volt instead of the battery 6 pack, connected series.
It can also increase the voltage from the battery 3 volt to 9 volt as well be the original circuit, and it will allow more current.
Properties of the IC TL496
- A TL496 be control circuit of the power supply, by the circuit was designed, so that the output voltage is 9 volt. For the change of the input voltage, which comes from the battery 1 or 2 pack. The TL496 operates in a switching regulator, the power loss is less than the typical linear regulator.

Read more source: http://www.eleccircuit.com/micro-dc-converter-3v-to-9v-using-tl496/

DPP adds versatility to VFC

The basic VFC (voltage-to-frequency converter) in Figure 1 comprises an integrator (IC1) and a Schmitt-trigger circuit (IC2). The integrator converts the dc input voltage, VIN, to a linear voltage ramp, and the Schmitt trigger sets the limits of the integrator's output voltage. Feedback around both circuits provides the condition for oscillation. The DPP (digitally programmable potentiometer) in Figure 2 adds programmable limits to the Schmitt trigger and adds two powerful features to the VFC.

Source: http://www.edn.com/article/CA257049.html

40KHz Voltage to Frequency Converter

This circuit was designed to frequency modulate a 40KHz carrier, using human voice frequencies. A common flip/flop is used at the core of the circuit.

Source:http://www.discovercircuits.com/DJ-Circuits/vco1.htm

Capacitor Discharge Ignition Circuit (CDI)

Capacitor Discharge Ignition Circuit (CDI)

DC13.8V to DC250V easy circuit

I have done a lot of work with valves in recent years. For me valves have many advantages, least of all the price; since they are now "obsolete" it is quite easy to get hold of them for next to nothing at rally's and junk sales. I recently purchased a couple of hundred battery valves for less than SEK1 (US$ 0.15) each.

The biggest problem with valves is the PSU needed to provide +250 vDC and 6.3 vAC for the fillaments. The transformers are no-longer available at a reasonable price, but a pair of 12v-6v-0v-6v-12v mains transformers will do the job just as well. For portable use only one transformer is required together with a pair of power transistors such as 2N3055 etc.

Above is the circuit of a converter that will generate the required volrages from a 12 volt source.

Above is the circuit of a converter that will generate the required volrages from 220 volt mains.

Just one word of warning: Dont forget to put a "bleeder" 100K - 270K ohm resistor accross the 250vDC output if your equipment doesn't already have one built in. Failure to do this can be fatal because the PSU smoothing capacitors can store a lethal charge for days.

Finally if you think that there is no place for valves in QRP or portable work then think again. An "EL84" will deliver 10 watts on the lower HF bands. It draws 300mA @ 6.3v (2.1 watts) for the heater as well as + 53mA at 250vDC (about 15 watts) for the anode and screen. The DC-PSU.GIF will provide this and draw less than 2 amperes from a car battery. A 48A/H car battery will therefore last over 24 hours NONSTOP TRANSMIT !!! If you also think that valves are difficult to build with then try one. You will be surprised.

Source : http://web.telia.com/~u85920178/

OBTAINING 250vDC & 6.3vAC FOR VALVES
by Harry Lythall - SM0VPO