11. You can check the receptacles in your house with a simple device called a circuit tester . 12. A screwdriver and circuit tester are probably the only tools you'll need to install a dimmer. 13. To test the transformer, touch the probes of the circuit tester to the terminals on the transformer housing. 14. You can check power at outlets with a circuit tester or simply by plugging in a small lamp. 15. A later development was the Marathon in-circuit tester , which as the name suggests measured viability of components in-circuit. 16. Use a neon circuit tester to make sure that the power is off and that the wires are cold. 17. The circuit tester will not light if the transformer is not delivering the necessary power to the bell circuit. 18. Circuit testers are available wherever electrical tools are sold, and a simple one usually costs less than $ 5.19. Using the circuit tester according to directions that come with the device, double check to be sure the power is off. 20. Use a circuit tester to confirm power has been cut to the fixture before using a screwdriver to disconnect the electrical leads.
