# Need with a circuit

• posted

hmmm... Trying to solve this problem for a long time But I dont seem to have enough knowledge to do so :( Ok...I have a circuit with 2 switches. they are normal on/off switches. if switch one is on then circuit must produce an equivalent resistance of 100 ohms. If switch 2 is on then the circuit must produce an equivalent resistance of 0 ohms and 50 ohms otherwise. How can I achive this? I tried almost all combinations of resistors and stuff but it doesnot work. I dont know much about transistors either.

• posted

"K. Civilian"

** Two 50 ohm resistors connect in series with switch 1 across one and switch 2 across both.

Open switch 1 & 2 = 100 ohms

Close switch 1 = 50 ohms

Close switch 2 = 0 ohms.

Open switch 2 = 50 ohms.

........... Phil

• posted

Do you mean ?

Sw1 Sw2 Resistance On Off 100 Ohms Off On 0 Ohms Off Off 50 Ohms On On 50 Ohms

• posted

And when you say "normal on-off switch" do you mean a single-pole, single-throw? It's easy to do what Richard has documented if you use single-pole double-throw switches. A 50 Ohm resistor in SW1's 'ON' position, the end of the resistor going to the 'OFF' and then to the wiper of SW2, which has a 50 Ohm resistor in the OFF line which then goes to the ON contact and is the other output. What you call ON and OFF in these switches is arbitrary, just so it works.

I've just busted up and moved 6m of concrete and gravel so I'm reasonably happy I can come up with that much! :-).

Ken

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