[DTMF transceiver connection]

I have a question how can i create DTMF tones with a MCU like 90S4433 or any other of the Atmel family, and how can i receive with a MCU with out any other component directly from the MCU with only a typical parts for the corect working of the device.

[Convert 0-30V 3A PSU to 5A or more]

Lisen the curent set from a trimer check that and the 10 A it is from the corect transform all the project it work with two comparative the one is for the Volt and the second it is for the Amber, you may use anything you want with this theory but you mast consider the transformer it has a registor that you must make her in the watt of the difference of curent limit with the max limit for examble the PSU has 10A max and 0-30v and you set the curent limit to have 1A out in a load of 5A you have 4A difference. Now with the Volt that you have for examble 20V the watt in the registor it is 80W this is the value that have the tranzistor for exable 2n3055 but be carefull the 2n3055 has some type with max A diferent from other. so you can use same similar to 2n3055 i don't remember the number but i will find them. but it is litle immoderete to have 10A to your place i have this PSU with 0-30V 3A and a 13,8V 10A and the only that i need is a PSU with -30V +30V 3A for some amplifier.

[Oscilloscope project]

Thanks for the web sites mixos it was very helpful.

[Convert 0-30V 3A PSU to 5A or more]

This construction it is very flexible i have see the same circuit to have an output 0-30v and 10A with limit curent the only ghange it was to same parts and of course the promlem with the temperature of the two tranzistor and the registor. i have this PSU but the 0-30v-3A for 5 years and i don't have any problem i'm thinking to do some changes to make it more useful like to increase the curent and to make it with a digital control of A and volt. I recommend this circuit to every one that they use electronics. The only way to change this PSU it will be a regulator that it will control the A and the V. I have found same of them like the L200 or the L123 but i have'd try this part yet.