Willen
Well-Known Member
It is a tiny Linear 50Hz transformer (iron core) rated 9V, 0.2A. Is it used on a simple 3 transistor audio amplifier circuit (PC speaker).
I didn't worked with transformer much. Today I tested its AC output with no load and got around 10.5V AC. I used bridge rectifier with high value caps and got around 13V DC.
I was trying to use it to another device (piano) which need 9V DC input supply. I was sad because tiny transformer gave 13V DC. But when I connected this 13V DC to piano, I got lots of voltage drop. The piano turned ON through this transformer and I got out only 8V DC output. I played the piano with LOUD sound and voltage was just 6V fluctuating. Then I learnt- small transformer (low Amp rated) drops its output voltage according to its load (load current). But 6V to 13V is very large potential difference. So if I didn't calculated Load current Vs Output voltage carefully then I will burn few more sensitive devices by using such power supply.
(piano needs 55mA current according to my poor Digital MM)
Are there any simpler understanding about such load current vs output voltage calculation?
I didn't worked with transformer much. Today I tested its AC output with no load and got around 10.5V AC. I used bridge rectifier with high value caps and got around 13V DC.
I was trying to use it to another device (piano) which need 9V DC input supply. I was sad because tiny transformer gave 13V DC. But when I connected this 13V DC to piano, I got lots of voltage drop. The piano turned ON through this transformer and I got out only 8V DC output. I played the piano with LOUD sound and voltage was just 6V fluctuating. Then I learnt- small transformer (low Amp rated) drops its output voltage according to its load (load current). But 6V to 13V is very large potential difference. So if I didn't calculated Load current Vs Output voltage carefully then I will burn few more sensitive devices by using such power supply.
(piano needs 55mA current according to my poor Digital MM)
Are there any simpler understanding about such load current vs output voltage calculation?
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