Sometimes, during installation or repair work a soldering iron for a long time "resting" while lying on the stand. This leads to premature burnout of the sting. To prevent this succeed, if at such moments the soldering iron will do lower voltage. But it needs to equip the machine stand, the scheme which is shown in Fig. 1. Such a stand was proposed earlier in [1, 2].
In the shown position of the contacts of push-button switch SB1 and contacts K1.1 relay K1 of the soldering iron, plugged in X1, serves a full supply voltage. This mode is necessary during soldering.
When the soldering iron is placed on the stand contacts the push-button switch is open. But the relay does not let go, because in effect the timer - charged the capacitor C1 discharges slowly through the resistor R2 and the emitter junction of the transistor. If for about six minutes to use the soldering iron is not will, the relay is released, the contacts K1.1 will open. The voltage on the soldering iron will to flow through the diode VD5, making the dissipated power on it reduced.
Once the soldering iron will be removed from the base, the contacts of the pressure switch. closes, the relay will and their contacts would short-circuit the diode VD5. On the soldering iron again will be served the full supply voltage.
Automation it is possible to equip already existing stand. For this you need to ve the front of the rack to attach a push-button switch and metal lever area for soldering tip (Fig. 2). If you remove the soldering iron handle is securely lifting the switch.
Relay K1 - RAS passport RS4.529.029-08 or RS4.529.029-018. The Capacitor C1 Is K50-CG, C2 - C50-24 or K50-33. In place of the transistor VT1 can be set, except specified in the scheme, any of the series KT815, CT, CT, but the first two you need to provide a small radiator
Literature
Author: M. Zhakiyanov, the town of Vyatskiye Polyany, Kirov region