Reply to "PW Whistle Detection Circuit"

stan2004 posted:

bmoran4 posted:

Presuming ERR has done all the engineering correctly, their bill of materials should be just fine:

JP1, JP2 2 pin connector 277-1273-ND
RL1 Relay 425-1210-5-ND
T1 Transistor (NPN) 2N3904FS-ND
C1 Cap 0.1uf / 50v radial
C2 Cap 33uf / 35v 6mm diameter, 2.54 mm leads, radial
R1 100k / .25w film resistor
R2 1k / .25w film resistor

The optoisolator is rated for a switched load of 3 amps. You may be able to find other optoisolators in the same family that have a higher switched current that may work for you if needed (but may have a different footprint).

There may be different conversations going on, but in looking at the ERR Hobby Corner page shown below, the above parts list is for the Post War Whistle Controller which does NOT have the DC detector circuit.

The DC whistle/horn detector circuit (referenced by the OP) is in the Solid State Post War Relay Replacement which has a different parts list.

Whopsies! I had the wrong parts list in the computer clipboard! I'm glad you caught that! This is the correct parts list I believe - note the Bi-Polar capacitor:

JP1, JP2 2 pin connector 277-1273-ND
RL1 Relay 425-1210-5-ND
T1 Transistor (NPN) 2N3904FS-ND
D1 1N4004 1 Amp diode
C1 Cap 10uf / 35v BP 6mm diameter, 2.54 mm leads, Bi-Polar!!
C2 Cap 68uf / 35v 7mm diameter, 2.54 mm leads, radial
R1 22k / .25w film resistor
R2 820 / .25w film resistor
R3 10k / .25w film resistor