vne147
Member
Hey everyone. I’m helping a friend of mine build a bench power supply and I’d like some verification that what I’m thinking is correct. We are going to use the NTE956 (LM317 equivalent).
First I want to determine the input voltage to the NTE956. The transformer we are using says 110 VAC 60/50 Hz on the primary side and 26.2 VAC on the secondary side. I’m assuming (maybe incorrectly) that 26.2 VAC is RMS voltage. If that is a correct assumption then when rectified, 26.2 VAC will become roughly 35 VDC.
(26.2V)*(√2) – 2V ≈ 35V
The 2V I subracted accounts for the forward voltage drop across the diodes in the bridge rectifier.
So with an input voltage of 35 VDC, we should be able to get up to 32 VDC (+/- a little) at the output of the NTE956.
Is this all correct so far?
Next question is that my friend wants to use an analog panel meter like **broken link removed** one. It has a range of 0 to 30 VDC. Could we damage the meter by applying 32V across it?
Thanks in advance for your input.
First I want to determine the input voltage to the NTE956. The transformer we are using says 110 VAC 60/50 Hz on the primary side and 26.2 VAC on the secondary side. I’m assuming (maybe incorrectly) that 26.2 VAC is RMS voltage. If that is a correct assumption then when rectified, 26.2 VAC will become roughly 35 VDC.
(26.2V)*(√2) – 2V ≈ 35V
The 2V I subracted accounts for the forward voltage drop across the diodes in the bridge rectifier.
So with an input voltage of 35 VDC, we should be able to get up to 32 VDC (+/- a little) at the output of the NTE956.
Is this all correct so far?
Next question is that my friend wants to use an analog panel meter like **broken link removed** one. It has a range of 0 to 30 VDC. Could we damage the meter by applying 32V across it?
Thanks in advance for your input.