Fig .1 Highly stable source of voltage schematic
Experimental studies of exemplary scheme of a highly stable source of voltage (Fig. 1) in the temperature range from -18 ° C to 50 ° C show that the temperature error of less than ± 0.001% / ° C, temporal drift no more than ± 0.005% per day. Source has a small thermal hysteresis (Fig. 2).
Fig. 2 temperature characteristic of source
Parts list :
- R1, R3 =1K
- R2 = 15K
- R4 = 6K8
- R5 = 2K2
- R6,R10 = 110 ohm
- R7 = 11 ohm
- R8 = 820 ohm
- R9 = 3K3
- C1,C2 = 10nF
- D1 = D818E
To ensure high stability in the scheme used the method of heating the crystal heating and temperature monitoring. To study the selected type of transistor assembly 1NT251 with Formula. Transistor Q2 is used to heat the crystal, and Q4 – a temperature sensor. Zener diode D1 – D818E. The operating mode is set for not more than 1 minute.
