Temperature-stable tuned-circuit oscillator, especially in a proximity switch
First Claim
1. In a transistorized tuned-circuit oscillator having a current source (Q), which is arranged in a circuit of a tuned-circuit transistor (T1), is controlled by a temperature sensor, which drives the current source (Q) high with rising temperature and vice versa in order to stabilize the tuned-circuit voltage, the improvement wherein the temperature sensor is a transistor (T1) thermally coupled to a tuned-circuit coil( L), the driving of the current source (Q) being performed by said transistor (T1) via a control circuit (S) which matches to one another the linear gradients of the thermally coupled transistor (T2) and of the tuned-circuit coil (L).
2 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to a temperature-stable transistorised tuned-circuit oscillator. Provided for the purpose of temperature stabilisation of the tuned-circuit voltage is a transistor T2, which is thermally coupled to the tuned-circuit coil L and controls a current source Q in the circuit of the oscillator L, C1, T1, in such a way that temperature-induced variations of the data of the tuned-circuit coil L are compensated.
-
Citations
4 Claims
- 1. In a transistorized tuned-circuit oscillator having a current source (Q), which is arranged in a circuit of a tuned-circuit transistor (T1), is controlled by a temperature sensor, which drives the current source (Q) high with rising temperature and vice versa in order to stabilize the tuned-circuit voltage, the improvement wherein the temperature sensor is a transistor (T1) thermally coupled to a tuned-circuit coil( L), the driving of the current source (Q) being performed by said transistor (T1) via a control circuit (S) which matches to one another the linear gradients of the thermally coupled transistor (T2) and of the tuned-circuit coil (L).
Specification