[Collins] 30l-1 with TS870

[Dr. Gerald N. Johnson, electrical engineer]

Well, the open circuit voltage on the 30L1 key line is at least 120
volts, some (Harbach) say 170 volts. The closed circuit current is 72 ma
by my circuit analysis. I've not figured the transient from discharging
the RFI bypass capacitors on that circuit. There is a resistor at the
connector to limit that peak current.

Whether the TS870 relay can handle those loads over many operations I
don't know. For sure its easier to install some sort of an external
device like an optoisolated MOSFET switch using a circuit I've proposed,
or that sold by Harbach before breaking the internal relay than after.
The external switch can prevent damage to the internal relay and make
its lifetime limited only by mechanical wear, not contact damage.
Stressed contact damage tends to be accumulative.

73, Jerry, K0CQ, Technical Advisor to the CRA
-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.