# Generating frequencies with transistors

#### tom10122

Joined May 16, 2014
6
How would I go about generating a frequency with a transistor?(Using a computer psu 12v rail) Can i Just use a small capacitance capacitor and when it charges up all the way have it discharge the transistor, using the small capacitor would mean it discharges fast enough to make a frequency?

#### Experimentonomen

Joined Feb 16, 2011
331
Try googling for oscillators.

#### tom10122

Joined May 16, 2014
6
Try googling for oscillators.
I thought about using one but I want to use 12v 3-4a for inductive coupling, and I couldn't find anything for higher currents.

#### ronv

Joined Nov 12, 2008
3,770
Why don't you spell out the objective. It will go a lot faster.

#### MrChips

Joined Oct 2, 2009
21,827
What frequency are you aiming for?
A 555 timer circuit is easy to build.

#### tom10122

Joined May 16, 2014
6
Why don't you spell out the objective. It will go a lot faster.
I want to be able to oscillate a coil with 12v about 3-4 amps (preferably) at a frequency (14 mhz if I did the math right), In order to wirelessly transmit electricity. I have Just about everything figured out except how to generate a frequency for the transmitting coil.

#### tom10122

Joined May 16, 2014
6
What frequency are you aiming for?
A 555 timer circuit is easy to build.
14mhz, would a 555 work for higher amperages?

#### MrChips

Joined Oct 2, 2009
21,827
At 14mHz, yes, but not at 14MHz.

#### tom10122

Joined May 16, 2014
6
At 14mHz, yes, but not at 14MHz.
Yeah sorry should've been more clear, 14 MHz .

#### m4lyg0s

Joined Apr 17, 2014
11
just wao , you guys want him to use the timer as a control circuit (14MHz) and a power circuit for the 4A ??? using something like Opto-isolator/triacs ???? , idk if that will work , assuming it will work , you need that type of wave? (square wave)

#### AnalogKid

Joined Aug 1, 2013
8,585
At that freq and current, it might be easier to drive the coil with a 14 MHz square wave and resonate the coil with a cap. Worked in color TVs since the 50's, although 4 A is a bit of a modification.

ak

#### wayneh

Joined Sep 9, 2010
16,399
I have Just about everything figured out except how to generate a frequency for the transmitting coil.
That's like saying you have everything for building a radio transmitter at 14MHz, except for the radio part. An RF amplifier at 14MHz and 4A is not a trivial part of your project.

#### tom10122

Joined May 16, 2014
6
At that freq and current, it might be easier to drive the coil with a 14 MHz square wave and resonate the coil with a cap. Worked in color TVs since the 50's, although 4 A is a bit of a modification.

ak
Thats how I'm resonating the receiving coil, I'll give it a shot thanks. Just thought it would be easier to build a circuit to transmit.

#### THE_RB

Joined Feb 11, 2008
5,438
How far are you expecting to "transmit the electricity"? And why the need for 14 MHz?

Electric toothbrush chargers use two coils placed near each other and run at 50 Hz or 60 Hz. Transmits electricity just fine.