1. Being able to sustain around 1kV while the contacts are open. At least 1kV before the initial contact closure. After that it gets hard t= o calculate since there may be residual energy circulating.=20 2. Being able to handle high current on contact closure. I'm closing a very low inductance capacitor into a small (10's of uH) induc= tance. Current will ramp up FAST. 3. Low contact resistance when closed. And low voltage drop, though mechanical contacts may be actually worse than= I think in real life. Still lower loss is better. 4. Are not worried about a voltage spec on contacts opening (is the recharg= e voltage turned on separately?)? Recharge happens as the contacts open, from a different inductor which has = been charging while the contacts were closed.=20 Current there is <1A, but the inductor is substantial. One of the nasty t= hings I want to reduce is the losses as the mech contacts open and close to= arcs across the contacts. The original solution with tungsten contacts work, but the contacts die (no= surprise) -----Original Message----- From: piclist-bounces@mit.edu On Behalf Of AB, Pe= arce - UKRI STFC Sent: Thursday, April 5, 2018 9:32 AM To: Microcontroller discussion list - Public. Subject: RE: [EE] Substitute for mechanical contacts Presumably you are really only interested in three things: - 1. Being able to sustain around 1kV while the contacts are open. 2. Being able to handle high current on contact closure. 3. Low contact resistance when closed. 4. Are not worried about a voltage spec on contacts opening (is the recharg= e voltage turned on separately?)? Its ages ago (like back when I was an apprentice) but an RT unit I used to = deal with used a relay with contacts about 3/16" diameter (they were lightl= y domed) to handle large currents for operating a 75W transmitter off 12V o= r 24V. I remember the contacts as being silver plated brass (don't recall c= oming across tungsten contacts), and I suspect you are after something simi= lar. I cannot recall if they would open far enough to take 1kV in air, but = removal of the back contact would allow them to open wider. These were a la= rge (about 2" x 3" footprint open frame relay without a cover, and I would = have thought something similar would suit your purpose. I'm afraid I don't = have any info on manufacturer or model, but at the time I always thought th= ey would be ideal relays to use for switching driving lights on a car ...=20 > Is there yet a device that will substitute for real relay contacts in an = AC circuit? > > I have a test fixture in mind, which is complicated, but the=20 > interesting part is discharging a low impedance capacitor of about 0.1uF = at 1kV into a coil, and allowing the current to ring down. > Spice tells me to expect currents in the kA range, and a prototype=20 > built with a relay contact seems to confirm this. Tungsten contacts take= a lot of abuse, and they also generate a lot of heat. > > Minimal voltage drop, ability to trigger "closure" and "opening" at=20 > any point in time, huge currents, and bidirectional currents without turn= ing off are all requirements. -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .