- Jan 1, 1970
David L. Jones said:found this power supply at DSE: K3435
Can be used in a variety of ways as either a single or dual supply
Designed so that constructors can obtain many different voltages: +15V,
-15V, +/-15V, +18 to 22V, or less than 15V [I need 4.5V]
Power source required: Power adaptor or transformer (depending on
Supplied with PCB and instructions only
Case optional (use H-2853)
PCB size:53mm x 71mm
Cat No. K3435
If anyone thinks this would work, good--just need to work out how to
switch it from positive to negative every 15min-- or maybe use 2 of
them through an AC to DC transformer--of course that may be easier
said than done...
We have already told you how to do it, but I'll re-cap.
1) A power supply for your "device"
2) A timer that can switch on/off at the 15min interval you want.
Connect the output of the timer to the relay coil.
3) A DPDT relay. See the link Andy posted on how to wire it up to
reverse the polarity when the relay switches.
4) A second power supply (probably 12V or 5V) to power the timer and
relay. This is only required if the voltage of your other supply is not
suitable for this.
In fact, you could use one of those common 24 hour mains timers - some of
them have plastic lugs at 15 minute spacings so you just need to push in
every second lug, and use it to power a low-voltage plugpack that energises