Telephone lamp as shown, when the night bell or lamp will turn on automatically when the hook, hang up to extinguish the lights after the delay 45s. Usually can be used for general dimming lamp without light switch. When used for light delay, delay as long as the touch of a button click, the light will extinguish after 45s delay. The circuit is a multi-use in one, mainly by the optical coupling circuit, light control circuit, negative pulse generating circuit, monostable trigger circuit, thyristor switching circuit and power circuit. The figure, IC1 pin PC817 4 Model selection; IC2 NE555 use the same type of time base circuit. So the best selection of 9014,3 DK4 VT switch; VS selection 1A, 600V ~ 800V Triac, such as 97A6, 97A8 and other models; regulator as 2CW60 such as 1/2W 12V. Use light resistance less than 1kO MG's MG45 models. C5 the best selection of CBB polypropylene capacitors, voltage 400V or more. Light bulb with a 25W or 45W H.
