need help

[chriosto]

i have a dc circuit operating on 9-12 volts dc with a frequency of 29 khz i need something to cut this circuit on at least 2 times a second without affecting the frequency,voltage or amperage. The circuit operates a high voltage generator that reaches from 0-100 kv any ideas?thanks

 

[MikeMl]

How much current does the circuit draw from the 9-12V supply?

 

[chriosto]

its out pu range is 0-150uA

 

[MikeMl]

its out pu range is 0-150uA

Is this from the High Voltage side, or the input side?

 

[chriosto]

the circuit its self has a working amperage of 400mA-700mA maybe thats what your asking thats the amperage going into the circuit the circuit is powered 12 volts ac off a tranformer the output of the circuit is 0-12volts dc the output of the cicuit is 0-12 volts 0-150 ua thats where i need the switch after the circuit before the module(high voltage generator)

 

[MikeMl]

Ok, so you need to turn on 9 to 12V at 150uA on twice a second. How long it is on each cycle?

I'm thinking a 555 set up as an astable mulivibrator running at 2Hz, XX? duty cycle. At 150uA, the 555 can switch the load on/off directly, without using a power transistor. It is ok to vary the voltage to the 555 from 9 to 12V; the load voltage will follow.

 

[chriosto]

thanks for the advice let me give it try n see if i have any problems i get back with ya thanks again

 

[Hero999]

What does the circuit actually do?

Please post a schematic.

 

[chriosto]

What does the circuit actually do?

Please post a schematic.

ok. let me start over here sorry i was reading the spec sheet on the circuit but it has been modified greatly so i checked the amperage and voltage and these are the actual readings i got.i have a voltage reading of 0-16.5 and an amperage of 0- 640 milliamps. i dont have a schematic on hand i will try to draw one up and post it.the circuit powers a high voltage modulator for a electrostatic powdercoating application.the circuit itsself works wonderful and has proven to be very reliable what im trying to do is get this circuit to switch on and off a couple times a second or pulse it doesnt have to shut completely off but it needs to drop greatly and rise back to full power very fast all the info on the 555 astable circuit ive found say it will only sync up to 200 milli volts wich is way less than what i need.also the frequency of the circuit is around 29khz i need this to stay constant in order for the module to function properly . any ideas? again sorry for the miss info.

 

[blueroomelectronics]

What is the circuit for? What is it's purpose?

 

[chriosto]

to power a powdercoating gun

 

[MikeMl]

What normally varies the voltage/current to the powder coating gun? Is it adjustable with a potentiometer? If so, is that varying the DC voltage to the Gun?

I'm trying to understand where you want to cut into the existing circuit to turn the gun on/off??? A schematic diagram of the existing circuit would help a lot.

 

[chriosto]

yes a potentiometer and yes that varies the voltage to the gun .the circuit has eight wires coming out 4 are for power in which is fed by a center tap 12 volt transformer,two wires go to the guns trigger when the trigger is pushed then it activates the hot wire going to the static generator in the gun the remaining wire completes the circuit.there is an led display connected to the board by a data cable this led display has a plug in on it where a 10K pot is attached this adjust the voltage/amperage coming out of the hot wire going to the static generator. with the pot wide open it reads 16.5 volts and 640 milliamps . what i would like to do is break or pulse the voltage/amps going to the static generator without altering the 26 khz frequency being produced by the circuit itsself i will try to come up with a schematic of the circuit if i can any ideas you guys have would be greatly appreciated i have tried several prebuilt circuits buut all have failed to do what i need it to do the closest thing was a pulse width modulator but it lost a lot of the power through the circuit and my display didnt work but the gun did function just not at full power

 

[MikeMl]

It sounds too complicated to suggest something without seeing a schematic.

 

[chriosto]

ok thanks mike ill try to get the schematic and upload it

 

[chriosto]

is it possible to create a pulse in a dc circuit at 16volts with .6 amps ive tried a start stop timer fromvelleman it has a defenent pulse but it restrics my output to about half . but it does exactly what i want it to. i also tried a pusle width modulator it just didnt seem to work but im sure i had it hooked up right i am going to post a drawing of what my circuit looks like but i dont have a shcematic.

 

[chriosto]

this is a drwing i need a pulse in the static generator any ideas? the switch turns the power on to the stati generator