Airian_007
Member
Hi,
I have a UC3842 IC which is working good when powered from a wall adapter (18V)
it generates pulses at the output pin n everything looks fine frequency is 100KHz
but when i power it directly from AC220 via 18(V) Zener and 100K resistor divider voltage drops. i checked voltage in parallel to Zener before putting IC in socket and it reads 18V but after placing IC in socket (Actually a Bread Board) it starts fluctuating between 15 to 10 volts and then rises to 15V and drops to 10 and it continues but when powering from wall adapter it operates normally no voltage drop. Zener is 18V (1/4W) and resistor is (100K 1W) and after bridger rectifire there is a capacitor (450V 300uf) and before rectification there is another capacitor parallel to AC plug non polar (0.1uf 250V) (dont know why its used).....
Kindly Help....
Thanks In Advance.
I have a UC3842 IC which is working good when powered from a wall adapter (18V)
it generates pulses at the output pin n everything looks fine frequency is 100KHz
but when i power it directly from AC220 via 18(V) Zener and 100K resistor divider voltage drops. i checked voltage in parallel to Zener before putting IC in socket and it reads 18V but after placing IC in socket (Actually a Bread Board) it starts fluctuating between 15 to 10 volts and then rises to 15V and drops to 10 and it continues but when powering from wall adapter it operates normally no voltage drop. Zener is 18V (1/4W) and resistor is (100K 1W) and after bridger rectifire there is a capacitor (450V 300uf) and before rectification there is another capacitor parallel to AC plug non polar (0.1uf 250V) (dont know why its used).....
Kindly Help....
Thanks In Advance.