When wiring multiple relays to trigger from a single low current output, how many 80-ohm coil relays can be safely connected at 12 volts if the output supplies 500mA of current?

To determine how many 80-ohm coil relays can be connected safely to a low current output of 500mA at 12 volts, one must first understand both the characteristics of the relays and the total current draw.

Each 80-ohm relay coil at 12 volts will draw a specific amount of current. Using Ohm's Law (current = voltage / resistance), we can calculate the current for one relay. With the voltage at 12 volts and the resistance of the relay at 80 ohms, the current drawn by one relay is:

Current = 12 volts / 80 ohms = 0.15 amps (or 150mA).

Now, if we have a power supply or output rated for 500mA, we can calculate how many relays can be connected without exceeding this limit:

500mA capacity / 150mA per relay = approximately 3.33 relays.

Since you cannot have a fraction of a relay, you round down to the nearest whole number, which is 3. Therefore, it is safe to connect 3 relays to the output without surpassing the 500mA limit.

Connecting four relays would result in a total current draw of