Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

problem on capacitor of timer

Status
Not open for further replies.

franticEB

Full Member level 3
Joined
May 10, 2010
Messages
152
Helped
1
Reputation
2
Reaction score
2
Trophy points
1,298
Activity points
2,540
Hi i have this circuit on board that doesn't show problems:

wd.jpg

then the designers decided to add a 200nF capacitor on cv pin in order to obtain a soft start of pulse signal in input to mosfet.

wd.jpg

I noticed a problem: when the -12v (timer is fed with negative voltage) goes to 0 there is a supply hole (50V) of about 20ms as if it were a short circuit.
when the -12v goes to 0 in the same circuit but without the 200nF capacitor there is not problems.
-12V is generated with self-holding circuitry starting from the output of transformer in figure.

Anyone could help me please?
 

It is difficult to figure out which of the ground symbols is really zero ground.

This is an unusual arrangement of two power supplies.

A lot of things will become more clear if you redraw your schematic so all wires are connected to something, with no ground symbols.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top